I go twice per year to Mexico and, since one year ago, at check out I ask the currency conversion they will apply.

Normally it is inflated but “acceptable”, nevertheless in the last 12 months, once at a Marriott and once at a Hilton, I had a bitter discussion at the reception with the FDM because the exchange rate they wanted to use it was crazy.
At the end one they accepted to debit my cc in USD and the other they accepted USD in cash.