needs TONS of dealers, and dealers from other casinos
in Vegas aren't going to get time off from their regular dealing jobs to go deal at the Rio just for that month, so they try to bring in dealers from all over the place and sometimes have to throw very inexperienced dealers into high stakes games.
They've done better in recent years at least making sure dealers only deal games they actually know the rules to, I remember back in 2008 my friend was playing 25/50 PLO and the dealer had no idea what they were doing, would constantly forget they had to deal 4 cards per player, couldn't tell who had won the hand at the end, and so on.
If any of you go play the WSOP, be super careful about dealer mistakes or miscues and speak up for yourself if you see them do something wrong.
That being said, you need to protect your cards at all time. Even forgetting about dealer error, if another player mucks their cards and they land combined with your, your hand can be ruled dead as well. Especially when you are next to the dealer, and ESPECIALLY when you are all in.