@HelloRaptor said:
Some people just like more or less pointless social gatherings that are just an excuse to get a bunch of people in a room together, explicitly without any larger goal or inclusion of sub-plots. This doesn't really address @Arkandel's sniper scenario, I'm just commented on the bit I quoted. Different strokes and all that.
The reason I mentioned it - other than my peeve on the matter - is that I literally don't consider that a PrP. It's a bar scene where the setting just happens to not be a bar but a festival, wedding, birthday party, whatever. I wouldn't bring a Sniper to one of those even if my own plot was all bullet-y precisely for the reason you brought up, namely that I'd figure the reason people go to these things is to roleplay having fun and not scrapping chunks of NPCs' brains off their clothes.
As for PrP crossovers, those are very tricky. Very, very tricky. It takes a great amount of communication between two STs before they can play with each others' toys in anything but the most simple of ways. For instance before I can let others play with Darwin's Creek - which is one of my goals - I'd need to sit them down and explain a whole lot of things. Even then, the storytelling process involves spur of the moment decisions, making shit up on the spot, responding to an unexpected question or action by PCs, adjusting to things the party decided to do... so then they have to sit me down to maintain internal consistency.
If it's kept really simple it can work without a lot of extra baggage and even then that's conditional. "So can you kill the bride's mother right when they are exchanging oaths?" is doable since relatively little information has to exchange hands, right? Yes, as long as the sniping is actually random and there's no connection between the people he's been killing.
There's a reason most PrPs are linear and combat based. "Help! I'm being attacked by monsters!" is hard to screw up; the PCs kill the monsters, the end.