The fact that they are sold in the gift shop does not mean they are used at the brothel.

If a casino had a promotional chip which they sold at the gift shop (the Palms had one) and an Ebay seller described it as being used at the casino most people would believe this is dishonest (perhaps unintentional -- but dishonest none the less).

That is my problem with these chips and how people including you are selling them.