Anyone got any good ideas to stop my 26 month old rascal unstrapping her seat belt harness in the car? Her dad is so frustrated he actually asked if we could smack her for this (don't panic my answer was "if you hit my child I will hit you" and he knows i will follow through and can beat the crappers out of him).

He is a very good dad, but old school raised. He would never hit her without my permission (which I would never give). But, he's getting to the end of his tether as I see by his messages (we share care 50/50).

Anybody got ideas?