So I'm asking what should I do here, if anything...

Two players, both on my right in a hand.
J93 on flop, c, bet, call.
Q turn, c, bet, call.
T river, check, check - showtime.

First player is a tourist callboxes who shows J8o while still holding it, second player is a reg as am I at this casino in vegas. Reg shows Q4s, tourist says "you got me." and drops his hand face up on the table, as does reg. Dealer grabs tourist cards and flips them face down on the muck...

Both hands tabled?

Yes you absolutely speak up and correct the dealer. Cards speak.

The rules state that every player has the obligation to point out mistakes reading hands at showdown. Pay no attention to morons that will say something like "OMG 1 PLAYUR 2 A HANNNDDDD." That has zero application at showdown with hands face up on the table.

..."Stop! Dealer, don't muck that hand, he has a straight."

And no, before someone asks, the dealer placing the winning cards into the muck by mistake prior to anyone stopping the action isn't a magic switch that awards the pot to the other player.

I know the rules, I was in a pot where the V actually stood up and threw his cards on the muck with so much gusto that they flipped, and he had a flush he didn't see. Someone spoke up but this dealer was better and grabbed the face up cards after the guy sat back down, he wins.

I basically said "dealer you may want to check the cards again, I think the wrong hand is mucked.". He grabbed the two cards and still didn't see the straight. So I said "8,9,T,J,Q." and finally the pot got awarded.

I was just asking because I was the only player that noticed and I play with reg a lot and I basically became the bad guy who awarded a tourist a decent pot from another reg because I follow the rules. No one else stays mum?

No. Because if you don't know where the money comes from then you stay silent.

Sounds like tourist tabled his hand to me and should get the pot.

Yup, this.

If he says "you got me", and pitches them face down, different story. But as told, everyone at the table has an obligation to speak up and make sure the pot goes to the right player.

Yes, I know. It just sux bc it was against the only other regular besides me in the game. He spoke up as well after the hand asking if the fish hadn't set his hand down would he still win blah blah...
I hated being the bad guy because of a bad dealer. O well, hope he doesn't hold it against me.

You weren't the bad guy.

He shouldn't. If he does, it's his problem, not yours.

Plenty of people stay mum because they're jerks. You did the right thing.

Not only did you ethically do the right thing, but calling it out was +EV for you because you'd rather have the tourist having the bigger stack than the reg.

Win/Win.

This sounds a little off. Are you saying you would let the best hand be mucked even if you knew the actual winner had tabled his hand and the dealer made a mistake?

No. I would speak up right away for the tourist. Besides being the right thing to do--I want the tourist to win the hand. More money in the tourist means more action for the table. And then the tourist thinks the game is fair and likes playing there. The tourist comes back and has more fun and potentially loses more money. Protecting the source where your money comes from is important. That's what I mean by my muddled statement.

Thanks for clearing that up.