I saw Mark post this in another thread and decided to offer my experience at G18 this past Tuesday night (cross-posted from another board)...
The police visited G18. They were there from 12:30 AM to 12:45 AM, and afterward many customers had to leave. I waited and watched until they left, then spoke to the door man at G18. He told me they told everyone to leave, but it was OK now, so I entered and enjoyed myself with no problems. It didn't seem like a real dramatic raid. It wasn't a secret -- the police car was in front with the red/blue lights on, so it was pretty obvious. Not sure about what they were checking, but I am 100% positive that they were in there for a period of 15 minutes, at which time at least 7 men exited. After they came back down the elevator, got in their car and left. That's when I chatted with the door man and he assured me everything was kosher. I went up, and all the girls and employees were still in-house, no problems.
I don't know about shanghai but here in beijing the police drive round with the red and blues on all the time. There are however an increasing number of unmarked cars many with blue and red flashing lights behid the grills etc just as they do in OZ. The ones to avoid are the PAP (Peoples Armed Police) vans with six or more armed police kitted up in body armour, these patrol all over beijing, the vans are unmarked but not hard to spot, if these guys attend your venue just duck.
teltel