What TGoat said...
Money moves lines, and not the majority of bets that went on one side. Let's just say 90% (100 total bets as our basis) of the bets went to the Lakers, but all of the bets were $10 for a total of $900 action for the Lakers, while the other 10% went to the Spurs, but the bets were $1000 each, that's $9,100 more on the Spurs action, and that will definitely move the lines...