Well this is FT after all, the place of finding and exploiting loopholes. I think there is very little difference of taking advantage of EF's and other mistakes and checking in people at the hotel. I realize that's a debatable point of view though.

FWIW the hotels I do this at know about this (I talked to the managers) and are thankful for the business coming their way. Without these status benefits it wouldn't make any sense for a regular guest to stay at a branded chain hotel in BKK. During normal times at least, now prices have crashed.