This I take with a rim of salt. I know resorts use cheap, no-name plonk to serve mixed drinks made by the bucketful. And I've witnessed too many drunks, binge drinkers, chug-a-lug and "Hidalgo" contests to believe a major resort chain will taint liquor. It's not unheard of for people - even in the US - to get sick, and occasionally even die, from acute alcohol intoxication. Add deep (or even shallow) water and a hot day, I can easily see a scenario for tragedy.

Drugging by a bad guy, just as in the US, is possible - Rohypnol is as available in Mexico as it is in the USA. Going anywhere and getting drunk is a great precursor to trouble. While I've seen this specific allegation of "tainted" alcohol before, I am not investing much credibility in it.

Yes. Just occurred. I have a lot of family there. They've faced issues - from scams to robbery to false and real abductions to attempted scams from law enforcement over the years. Then again, they know (mostly) how to cope, wherevtonavoid, etc.