Well...there seems to be one around Lancaster, Pa.. Coming into a cg one afternoon, the owner of a brand new motorhome didn't want to wait online to register. So, he entered the CLEARLY MARKED "Exit Only" lane....ran over the treadles and promptly blew out all 6 tires.
Took about 6 hours, I think, but new tires all around. VERY expensive weekend for this guy and a VERY angry wife.
As far as what you want to do....I suggest you replace your tires at a shop...and use the "portable" guys only for an emergency like a blow-out. Seems most shops now use balancing beads (like "Equal")....easy and fast...and they work....no reason why a on-the-road guy wouldn't use them either.