I stayed here and several days after checking out, I received two emails it Portuguese that seem to be from some local government office about a tax and a security guarantee. (In a week or two, I'll be able to have someone from Brazil translate for me and explain what this is about if it's legitimate.) I'm afraid to click on the links. The emails definitely refer to this hotel, which is the only place I used my credit card in Sao Paulo, and were sent to the email address on my Marriott account and reservation.

Can anyone guess what this means? Or does anyone know a safe email contact at the hotel to whom I could forward these emails to report this?

I've stayed in four other hotels in Brazil (none were Marriotts) during the last two months, using the same credit card, and didn't get any such emails. In the meantime, the credit card seems to work fine, although there was no obvious reference to my credit card in the emails. It seems very strange. I've never received any such messages through a hotel in more than three decades of extensive international business travel.