Could this be how it works at Comet? When you show up with your children and see other kids playing in the ping pong area, are you going to check that they're all there with their parents? Of course not. This is a restaurant with alcohol and adult live entertainment and yet its customers will think nothing of seeing lots of small children late at night running around.

So a client shows up. Gets taken the back where one of the slaves are and then leaves out the back where he can jump into a car or the back of a van. Live entertainment means nobody would find a van parked round the back out of place.