At the AMPs, I saw Grace at Bikini and 333 when she was the mamasan but had seen her for years before that. Actually did a fair amount of off-the-clock stuff with Grace.
Also did a session with The Queen when she ran Fantasia; caught her early in the morning when she was horny and I was the "victim" du jour. She nearly killed me.
At the Chinese places, the lady who answers the phone is often not even on-site. Of those who are there, it's very hit and miss. Sometimes money talks, but I don't know if I'd want to spend a couple hundred bucks on a body rub. However, at many of the places the front door lady is actually the owner or manager and as others have said, they'd rather see you than see you leave.