4yr old undoing his seat belt

[dummytit]

Anyone knows how to stop my son undoing his belt.I have bought angel guard but i can not undo his belt to get in or out too safe!

when DS went through a phase of doing this we bought one of these until he got bored of trying

we bought a brio signal (his choice) if he did a 6 hour journey without taking it off. he got the signal and never undid the belt again.

crelling are supposed to be good for escape artists. Our friends got one for free via the NHS occupational therapy dept