I'm not triple-dipping on PC chances to spot deception, which seems to be a common here:
1. GM speaks in character as NPC - player has opportunity to tell if NPC is lying.
2. NPC always has to roll Bluff vs PC Passive Insight, if fail then PC auto-detects lies with their lie-radar EVEN IF THEY HAVE NO REASON TO BE SUSPICIOUS. I find this incredibly implausible, it ignores real-world social dynamics. It also means players never have to engage their own grey matter. It really sticks in my craw.
Like I said, it does come down to a certain extent to how much you want to weight player skill vs PC skill. Like with other social skills, it tends to be an area where you can easily marginalize certain PCs because of these sort of expectations. No one expects the fighter's player to physically be an olympian in order for his character to climb mountain and jump across rivers.
But if the person playing the skilled investigator is, as a person, not as adept at picking up on whatever 'clues' the DM is offering in their NPC speeches - and instead wants to rely on having a character who is supposed to be good at that - it can come across as somewhat unfair to force them to rely on their own abilities (while the fighter, who is played by a smooth-talking and quick-witted player, ends up thus being good at
everything.)
But again, player skill vs PC skill is a tricky debate, and both styles of play can have their advantages. I can understand why you wouldn't want to give players too many chances to see through a clever ruse. At the same time, having NPCs who shouldn't be at all skilled at lying who instead easily pool the wool over PCs eyes, just because they don't ask the questions you want them to ask, can end up a frustrating scenario. In my experience, at least.
3. NPC makes check vs passive Insight vs PC. If player seems the slightest bit less than totally oblivious, the DM informs them they can roll an active Insight check.
I think some of your three part description here might be a bit exagerrated. More often, this is what I find:
1) The DM tells the players what the NPC says. Sometimes there might be outright contradictions they can pick up on to tell that the person is lying. That tends to be the exception rather than the norm, however - typically, there isn't any immediate evidence that something is untrue.
2) The DM rolls Bluff vs Passive Insight. If the NPC botches it, then yeah, he tells the players it is pretty clear this guy is trying to scam them. A closer roll might just tip them off that something is unusual, and they can try to use their own abilities to figure things out in more detail.
3) If the players are suspicious or ask to roll Insight, they can do so. This idea that the DM goes aheads and prompts them to do so for no reason seems relatively unlikely to me.
Compare to PC trying to deceive NPC - either the GM lets it pass if the NPC has no reason to be suspicious, or the GM is a stickler and forces a Bluff check for everything. Even then, the PC only has to beat NPC Passive Insight to succeed - one dip, not the three the NPC had to get through.
I guess part of my disagreement here is that your approach seems to be, "Anyone can easily tell a successful lie if the other side has no reason to be suspicious."
And that just doesn't make sense to me. Lying, like many other skills in D&D, is something we have a codified way of measuring. If someone isn't suspicious, that might make it easier, but the entire point of having a Bluff skill and an Insight skill is to measure how good those people are at either telling lies or seing through them.
Saying that the DM is a 'stickler' for requiring a Bluff check every time the PCs
try to lie is like saying the DM is a 'stickler' for requiring an Attack Roll every time the PCs try to hit an enemy!
Sure, I guess you can in some cases handwave either of these scenarios. If the bard is trying to con some 1st level commoner or the warrior wants to go stab some chickens or whatever. But in most cases, if a PC is lying to someone, it doesn't seem in any way unreasonable for me to expect them to roll a check to see how clever a lie they tell. Now, getting back to player skill vs PC skill, I will quite often let RP have a big impact there - telling a well-thought out and convincing story will often give them a big bonus or the like, and yeah, if they accidently slip up and state something provably false, many NPCs might pick up on that.
I think there's a place for passive insight in certain circumstances, but normally as DM I give plenty of in-character signs an NPC is lying, and if the player isn't even suspicious enough to request an Insight check I don't feel obligated to have the NPC roll Bluff, just as a PC wouldn't have to roll Bluff vs a non-suspicious NPC.
Do you have any examples of what you might consider scenarios in which lies would be told to non-suspicious NPCs?
