Happened to me in Malaysia. The bottle of shampoo I had in my suitcase came open, and the plastic bag it was in leaked. So I had several items I had to wash out in the hotel tub.

One of them was a black sweater, and the dye ran. I rolled the washed sweater in a couple of bath towels to try to blot it, and dye cane off on the towels.

I didn’t think much of it, but a day or two later the front desk said they were charging me $10 each for them (they were not the greatest towels, either) because they could not get them clean. I wonder if they just washed them in hot water with all the others and that caused the dye to set.

At any rate, I had to pay, but I told the FD clerk if I were paying for the towels then they were mine and I would be taking them with me. She seemed shocked at first, but later someone brought them to my room. I used them for various random things once back home, and eventually the black washed out of them.

In order for this to be a valid way for hotels to protect their investment there must be a before check in room inspection and inventory counting with the client and hotel staff (how many towels- if there is ia working coffee maker etc .)At check out there should be a post inspection with client and hotel staff for the same . If the system is to be fair then they must insure that there were exactly 2 large towels 2 small towels a coffee maker -a bathrobe when I checked in and not charge me for that when I checked out.
When you rent a car there is a pre rental inspection and a post rental inspection with a rental agent .
In order for this to be legal there would have to be the same , and there is not .
This practice needs to end it is illegal .