Nah, everything was cool. They just came to check out why the hell there were 50 cars in a parking lot on a Friday night.
They said they were watching us in their car for about 25 minutes, then walked over to check things out. They were cool, just asking what we were doing, what the common theme was, etc. They said us being there was no problem at all. And they were pretty funny.
There _was_ a bit of an exodus after we were talking with them for a little while, but all was fine.