Now, this seems pretty much on the ball. It is something that would need to be disseminated among members and brought to people's attention. But, it seems like it has a pretty good handle on things. Chain of complaint - GM, coordinator, venture officer. And a warning to others to be respectful.
So long as this is actually acted on, it seems like they have a decent handle on things.
And no mention of threatening to throw people, which was a rather large part of some of your earlier posts. That was my biggest problem with your earlier comments. Simply telling people to be respectful and mindful of those around them is a world away from some of your hypothetical situations that very consistently included the phrase, "or you will be asked to leave" or something similar. Formal warnings like that I would expect to primarily come from the venture officer and only after the lower level people have determined that someone that high in the chain of command needs to be made aware of the situation.
Your earlier statements made it sound very much like you assumed the first responders, like the GMs, could and should routinely be throwing around warnings about being kicked out before there was any justification for that level of warning or threat. I fully agree that the best way to handle it is for the GM first, and since they probably saw it happen, they don't need to answer further questions or get more information. If, however, it gets beyond the point where the GM or staff member saw it directly, the idea that the complaintant doesn't need to provide any more information or that simply talking the supposed offender is the best solutuion doesn't always work. At a game store, it's still probably not that hard; it's a small space and mostly familiar faces, so even if one of the store workers didn't see it directly, they were generally aware enough of what was going on enough that they could respond pretty quickly without needing further information, and the person that needs to be talked to probably hasn't moved very far.
Conventions are a lot harder in almost every regard. People move around a lot and the number of attendees quickly dwarves the available staff (whether they be volunteers running events, formal security, vendors, or the organizers keeping everything moving in the same direction), and your really nice idea goes out the window very fast. Individual events (like the collection of PFS tables in a single spot being watched by PFS volunteers) can keep that to a large degree because they are essentially contained units within the larger structure of the convention, and if the complaint is made in a timely fashion, your idea still works fantastically as long as both parties are actually involved in that event, and one of them wasn't just passing by. Also, the bystander issue doesn't really come into play at this level, so even the venture officer can generally act fairly quickly without that being a major concern.
I suspect where most of the problems at cons occur is outside of these micro environments and come up far more often if there's a room of tables set up for open play or a room full of vendors with constant milling around or something similar where there is no clear GM or reporting structure right there to deal with problems. At that point, anyone making any kind of complaint is by necessity going to have to provide more details in order for the staffer to even begin to know where they need to look to find the offending person to talk to them. That is where you idea breaks down; the staffer has at that point a number of equally time consuming options to consider, as simply talking to the offender is not actually all that simple. They may find it best to make sure that the person with the complaint is away from the immediate problem and than inform the rest of the staff to be aware of the fact that the complaint was made and that they need to be reminding people that this is a public space. Especially if it seemed to be a complaint about a random comment, trying to track down the offender to give them a warning may very well not be worth it, especially at really large cons where it could take a long time to track down a single individual. If the complaint was from a specific area, the staffer could make sure that that area in particular gets the message, but much more than that could be very difficult to justify if there was no further details provided beyond "I felt harassed."
Ultimately, your idea is the best solution, but it tends to have scaling issues. It makes perfect sense for a game store or a highly organized event/group, like PFS, to operate under those expectations, whether they be informal or a formal written code; forum moderators can usually also function at this level without too much difficulty. Convention staff in general are simply not going to be able to operate under those expectations. There is simply too much they have to look after at any given moment, and any action they take is going to take enough time they need enough details to know that it is indeed the right action. "I was offended" or "I was harassed" is not enough information for people at that level. The best solution at that point is for the community to step up and keep an eye out for when things are starting to get a bit hot and stop it before it occurs, because once it occurs, if the convention staff have to invoke their formal policies, the victim will likely have to answer as many questions as the accused. You can say err on the side of caution and respect for the victims all you want until you are in that kind of position where you really do have to determine who is right and how to address the problem with both sides expecting fair treatment. In real life scenarios, it is a lot harder for someone in that position of not having any kind of previous knowledge of the people or events involved to do anything simply and quickly or to visibly err on the side of caution by basically taking the accuser at their word with no further inquiries before taking action. After all, the person that you may have just falsely accused of harassment paid just as much as the accuser to be there, and they probably have just as many friends or supporters to back them up.
At some point, the accuser has to be realistic in their expectations of what convention staff can actually do, even if most of the people on the staff would love to be able to do far more. Making a complaint to a DM about a comment that was just made in within a set group is very different from going up to a random convention staffer and complaining about something that happened in the randomness of the convention. What can be reasonably expected from all the parties involved is completely different, but too many people see a blanket policy like what you are proposing, and assume that it's implementation is going to be the same every time. Even if you personally don't expect that, enough people do that it can cause big headaches for convention staff, and often enough, even in smaller, more contained spaces like a game store.