I would hope that untrained and more importantly unlicensed crew are discouraged from conducting repairs on required safety equiptment when there is a safe alternative available.

If seat belts were there solely for the individual passenger's safety, all that would be necessary is a "common sense" warning, e.g. "if you are smart, buckle up." But, that is not the case.

I could care less if the idiot across from me buckles up if the sole consequence is that he injures himself and if he does, the flight continues with him in agony. But, if his stupidity places me at risk, the idea of requiring that he be in a seat with a properly-functioning seat belt and that it be belted, seems reasonable.

What next, "a bt of a rattle in that flight computer, but no worries, I've some Super Glue here --- it's off over the Pole we go."