Andres,
It is quite possible that this is the case. HF by itself has little effect on plastic but does dissolve glass, and will attack metal too. The fake chrome you talk about is actually (in most cases) vapor deposited aluminum covered with plastic. I have seen more affect on plastic from the caustic products than the acid.
Here is how it is typically used in a touchless car wash. If you get a deluxe wash with 2 soap passes, the first pass is a low-ph (acid) soap designed to specifically cut through the grime on the glass and trim. Its action is almost instant; it is a reaction. If you only have one soap pass, it is with all certainty a hi-pH product.
The second pass is the hi-ph (caustic) soap. Hi-pH is normal for detergent--be it the kind you wash your hands with, dishes, or clothes. This 2nd pass does two things: first, it must neutralize the acid from the first pass. It then must have enough residual strength to remain hi-pH in order to cut through the dirt on the rest of the car body. This takes some time, and the industry calls it dwell time or soak time. Then comes the high-pressure rinse, followed by any waxes or other things you may have purchased.
If you think that is a bit tricky to balance, you are right. You have to maintain a balance of acid/alkalinity in the products, maintain dilution; and you had to measure such with titration kits. Then you also had to measure pH on the car with test strips. Yes, that's running into the wash with test paper after soap application and before high pressure rinse, watching out for moving arms! Even when your titrations and pH were on target, the effects were all changed by temperature, water quality, and seasonality.
I washed nearly 15,000 cars a year in my touchless (sold the car wash last year) most with out issue. Every now and then I'd come across the most peculiar things--cars that simply would NOT come clean without friction, no matter what you put on them. In one case, a regular customer's windshield got this haze on it that would NOT come off. The glass had to be buffed out itself! (thank goodness the owner was a detailer else I would have paid!) Had seen that only once; it was clearly some chemical reaction with something on the glass.
I used at first, a glycolic acid based product that was very good. Problem was it was not THAT much better than traditional acid products (but 2x the price), so I switched to a traditional phosphoric-acid based first step product.
Remember I said that the first step--the acid--was used for glass and trim? Have you heard that old "wive's tale" about using Coca-Cola to clean your windshield? Read the ingredients. Phosphoric Acid.
When examining the car wash floor, understand that all acids will etch concrete. So you kind of have to compare it with others to know what is normal etching damage from safe acidic soaps, and what is
extensive damage from HF or Ammonium Biflouride.
http://www.carwash.com/articleprint.asp?print=1&IndexID=4230101A mildly-soiled car that gets washed regularly will get about 90% clean in the touchless wash; the rest of the 10% is generally loosened and will come off with a hand dry.
