I’ve been eating burgers cooked medium (145 degrees F) for 30 years, and never get sick. Is it a Canadian beef problem? If the hotel is that worried, just refuse to cook it less than 160 and let them order something else. But no, capitalism says that Hilton must take their money and make them sign a waiver that probably has zero chance of holding up in court.
You actually just need to get your ground beef from reputable places, and well, I sincerely doubt Hilton Hotels cares enough to do that. My butcher grounds his own beef from chuck, sourced locally, and I don’t have to cook my burgers to sawdust to feel safe about eating them.
I’m not your guy, pal.