Olympic swimming pools?

Question

Ok, this question doesn't exactly apply to only Olympic swimming pools, only the ones for like national/international competitions and stuff. When the swimmer reaches the end of the pool at the end of the last lap, who pulls the switch or whatever to release the big banner thing displaying their name and position? Or is it like motion sensored or something? How do they know the exact time when the swimmer reaches it? What if they 'cheat' and wait like a second later?

Answer 1

when they say snooker and pool, they mean billiards games, not swimming pools.