I always just asked my players what they would prefer if another character was betraying them. So if one guy DOESN'T WANT TO KNOW and knowing will ruin his fun / make it impossible to ignore, then if people are doing something to him or around him, they just tell me. Other players want to know, and gladly play it up by like offering to show the other character something interesting that they otherwise wouldn't have seen. It's a tricky thing to do right though so you got to be careful. I've definitely prompted players to see if they read a sitch under the right circumstances... but:
Joe plants camera's in Nick's room. Nick goes into his room, and I tell him the scene is charged. He now makes his obligatory read a sitch roll, and then looks at the room. Many of these questions wont have real answers, and so I'd have to ask him to make another one. Questions about enemies would probably highlight the player but not why which is odd, cause it's hard to describe why he knows this without knowing about the cameras. And of course, there's always one or two of the options that will immediately reveal the cameras.
...
They get to pick 1 on a miss, so... telling them the sitch is charged might end up being just the same as just telling them they automatically find the cameras. This is not cool for either party. Play responsibly. ( Having had many games like this, with subtle PvP, I find the players are actually the best arbiters of this knowledge. You only lose potential by hiding it, unlike in a game like D&D where it's almost mandatory you keep it a real secret. )