Neonchameleon
Legend
I know of one time it's been done well. But the reason that time worked was that nothing in the bait and switch changed the nature of the characters the players had designed.
What it was pitched as was a modern day detective game centred round a PI's office. Where the bait and switch came in was that it was actually a modern day game of Call of Cthulu (using GURPS rules, so it wasn't obvious) with the PCs being centred round a detective's office. Except that not every cult was to do with the mythos. This left the PCs remaining as the PCs doing exactly what they would under the circumstance.
The worst one I've been subjected to was when the Storyteller actually re-wrote my PC's background with amnesia to make it that he had set off the chain of events we were running from - both in a way that was completely OOC from him and in a way that defied common sense (and my understanding of the relationship between the seelie and unseelie in Changeling, but that's another story). No. My PC is my PC. You might be able to put hooks there. But this is my area of the gameworld.
On the other hand I'm doing something similar to someone else. His character concept was that he was [low level boss] brought back as a Revenant with amnesia. Unfortunately [low level boss] has a very powerful patron who's meant to be the end boss of the AP. So PC believes that [good deity] brought him back but was actually brought back for reasons of his own by [BBEG].
What it was pitched as was a modern day detective game centred round a PI's office. Where the bait and switch came in was that it was actually a modern day game of Call of Cthulu (using GURPS rules, so it wasn't obvious) with the PCs being centred round a detective's office. Except that not every cult was to do with the mythos. This left the PCs remaining as the PCs doing exactly what they would under the circumstance.
The worst one I've been subjected to was when the Storyteller actually re-wrote my PC's background with amnesia to make it that he had set off the chain of events we were running from - both in a way that was completely OOC from him and in a way that defied common sense (and my understanding of the relationship between the seelie and unseelie in Changeling, but that's another story). No. My PC is my PC. You might be able to put hooks there. But this is my area of the gameworld.
On the other hand I'm doing something similar to someone else. His character concept was that he was [low level boss] brought back as a Revenant with amnesia. Unfortunately [low level boss] has a very powerful patron who's meant to be the end boss of the AP. So PC believes that [good deity] brought him back but was actually brought back for reasons of his own by [BBEG].