Spirited Away. Both played straight in the beginning with Chihiro's parents, and averted at the end, when she's told not to look back in a scene reminiscent to Orpheus. She almost does, but her willpower is strong enough not to look back.
The Simpsons Movie, Agnes Skinner: "Don't look where I'm pointing!" She was pointing at Bart's penis.
Aladdin. Just before Aladdin and Abu enter the Cave of Wonders, it gives a stern warning: "Touch nothing but the lamp!" Exactly why isn't made clear until Abu grabs a giant, conspicuous ruby. Let's just say that our heroes were pretty lucky to have met the Flying Carpet.
Scar from The Lion King uses this on Simba (a cub at the time) to lure him to the elephant graveyard. True, he doesn't realize that maybe Uncle Scar isn't trustworthy...