MechaPilot
Explorer
One of the issues I had with 3E power creep was that I simply did not have the time to read every new sourcebook--whether from WotC or a 3rd Party product--that landed on the store shelves.
Of course DMs have the right to limit content, but if a DM is going to make that decision he or she out to take the time to read and understand the content. Spending $20-$40 on a book just to have a DM say no without so much as a look at it is bad form.
Who is buying a $20-$40 book with the assumption that they can use it in their game without first talking to the DM? Certainly not someone who thinks that $20-$40 is a significant expense or they would have asked first. And what DM who places restrictions on content isn't telling the players ahead of time? That sounds like a DM who is just begging for a misunderstanding. For example, I don't allow teleportation; if someone wants to play a caster, I tell them about that restriction so they don't expect to be able to get that ability several levels down the line only to be disappointed.
All you are describing is a player buying a book without thinking, or a player buying a book because the DM didn't make it clear what was allowed and what was not allowed ahead of time. In both situations, you have one careless person creating a problem for someone else. Careless people do that all the time, and it's their own fault, not the fault of the options they impulse-purchased or forgot to say was banned. Hopefully the one who bought the book kept his receipt so he can at least get store credit out of it.
Spending $20-$40 on a book just to have a DM say no without so much as a look at it is bad form.
Bad form for the player. You don't get to force the answer you want from someone just because you went ahead and did something without their permission. Now if the DM didn't make her position clear ahead of time, then she's the careless jerk.
It's not as simple as issuing a yes or no.
It really is almost exactly that simple. Let me use myself and my players as an example.
The players can use any option in the PHB except for the handful of things (such as long-range teleportation) that I have specifically excluded. That is all that I guarantee I will allow. If they want to use something else, they can ask me about it, and I will give it due consideration. I may say "no." I may say "yes." Or, I may say "yes, but with modifications or conditions." I have made that very clear to them, and none of them expect that they can get me to okay something just because they shelled out cash for it. What they spend their own money on is really none of my business.