Practically-speaking, joshua doesn't have a bad idea. But the city wouldn't see it that way.
Getting to your question, CarGuy, I've never, ever been "checked" and I rarely break out the water reclaim equipment. And I don't use rinseless washes either - most non-autopian cars are too dirty for this method, IMO. So you could use the rinseless solution, and gamble by washing the regular method when necessary. Also, as long as you are washing at people's houses and you don't have a giant rig with "Mobile Detailing" stickers all over it, nobody is going to know you aren't washing your own car in your own driveway anyways.
The whole thing rubbs me the wrong way...across the street from one of my clients is a giant parking lot that gets steam cleaned every other week...and they just let the oily water run down the storm drain...and here I am reclaiming water from a few vehicles here and there.