Hilton is bad about maintaining eMail addresses so buying other lists is not out of the question. I changed my address a couple of years ago and I am still getting messages to the old address even after I have contacted them several times to purge the old address. I have not gone to the point of having a personal domain and assigning each chain a unique address. So far Marriott is the only one that has shown up on non-Marriott mailings.

Unfortunately, marketing people use metrics to prove their effectivness, so the more they send the better they are. It doesn't matter if it's duplicates or to people who don't want their message. Back in my catalog production days we called that "thud factor", the louder the sound when it hit the table the better the catalog. No longer in that business.