I've wondered about these too BenzOnline. Having recently returned from a trip to Eastern Washington (read: sandy, snowy, roads including a snowboarding trip) we returned with my Mom's CRV (which she was then trying to sell) absolutely filthy.
Not being up to washing the beast, I took it through one of these 'no-touch' carwashes and got the 'platinum' treatment including the 'wax-and-clear-coat-sealer' or whatever they called it.
They have a guy come out with long handled brushes who, after rinsing the car, proceeding to wash it with the brushes they dipped in huge 50 gall drum of sudsy water (which was black from previously washed cars) before they sent me in to get the foamy treament.
Afterwards, water did seem to bead a bit more than previously, and the car was much shinier (but this might have been exagerrated considering it was sooo dirty before). Overall not a bad arrangement if one needs a clean clean car and no time for a good hand wash. Would I take my benz through it? Not on your life considering the dirty-black wash-water, and the attendant's reckless scrubbing with those brushes (nylon? poly? who knows what the bristles are made of and how gentle they aren't).
Anyway, if you wanted some quick protection, don't see why you couldn't hand wash yourself and take the car through for the 'wax'. It probably wouldn't last much more than a week or so, and considering the $7 it costs - I'm sticking with the time-honored tradition of hand-washing/waxing my own cars
Regards,
- Ryan