Say you have a small outfit, like an Asian massage parlor, it has a set location, customers come and go.  Isn't that kind of high risk?  Certain... "people" seeing all the random people come and go?  Educate me on this please..

as there are a lot of independent ladies who provide massage and with the AMPS you stand to run into a lot of upselling.  
Generally though, if an AMP has been up and running for some time, they are greasing the skids somewhere and are protected at least from local LE - this does not mean they cannot be busted by county or state LE...
Steer clear is my best advise on this.  The risk is just too high.

It would be a good idea to stay away from the AMPS in that area.

(This is close to what happened in Connecticut a few years ago.)

on if local LE has a hard on for the "prostitution problem".  Usually they don't, unless there are a number of complaints (the public nuisance factor).

If they've been around awile (trust me LE knows what goes on there), you are likely safe, but things can change with one call to the mayor or police chief.

LE being one of them but more important to me at least is the sheer volume of guys that these poor girls are forced to see in the average day.

You bring up a good point regarding LE but it is ironic that everyone is advocating avoiding AMPS and one of your concerns is the volume the girls "process". I think that if they are seeing that many guys then no one is listening to staying away. However, although I would like to think that they get a good volume of clients my experience has been just the opposite. They are not getting the volume we are lead to believe and that is why they don't stay around very long (Other factors considered like service, LE, erc.)