Yogi Bear ultimately stops Boo-Boo becoming zoo attraction? (7)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

last/ultimate letters of [Yog]-I [Bea]-R stopping inside GAFFE="Boo-Boo"=minor mistake/accident for the surface reading, Yogi Bear and Boo-Boo are both cartoon characters from The Yogi Bear Show