How you can tell a Straight game from a Vegas trap game?

I think people misunderstand the concept of "trap."  It doesn't mean the trap side will win 100% of the time. That's impossible.

But OTOH, bookies set a pointspread for a reason.  In almost all games one side has a higher probability of winning.  So they create a pointspread.  Supposedly, the pointspread handicaps the stronger team so that both teams have an equal chance at "covering" the bet.   

Plenty of time, I imagine the collective betting public correctly perceives the pointspread. But occasionally I believe oddsmakers (who make a living analyzing sports) believe there's a different probability than what the public perceives. That, IMHO, is what makes a "trap."

For example, let's say bookies set a pointspread on an NBA game, such as LA Lakers -6 at NO Hornets.  But let's say the bookies know the Lakers have only a 40% chance of covering.  And the Hornets have a 60% chance.  If 70% of the betting action is on the Lakers.... then why move the line???   Why make the line higher and attract NO Hornet bettors??? That's stupid.  You're giving away money.

Will Vegas lose sometimes? Sure.  The Lakers will cover 40% of the time.  But if oddsmakers are right -- and  I don't know any casino that's ever shut down its sportsbook b/c it lost $$$ -- then they'll make waaaay more money than trying to get equal action on both sides.

That IMO, defines a trap game.

What amazing to me is that most ppl notice a "trap" line but tend not to pay it any attention, two examples that were crystal clear who was going to win.

Astros second game againt the Cubs on the road where the are a joke, yet they were at even money, make no sense right? Houston won

Last night pre season football.....how are the sorry ass browns ever with in 3 pts of Green Bay, whole word jumped on GB and they lost straight up.

If you know what to look for Vegas is telling you which side to go.