Computer is the last word

Speaking with a pit manager today while playing some blackjack and we were speaking about card counters and I asked how they really know who is counting. I know it’s a dumb question but I was making conversation. He goes on to tell me that he knows when people are doing it because he counts as well but he also stated that they don’t always kick people out UNLESS the computer tells them to kick out the person. This is sands Bethlehem aka wind creek btw

Usually it's when you're watching other people's cards more than your own.