Here's another one, along the same lines.
If confirming a person is not dangerous before allowing them to be in a position to harm others easily is a good thing, why limit it to gun purchasers? What if the background check were opened up to anyone who felt like checking out another person, for whatever reason, subject to a small and reasonable fee.
Hiring a babysitter? Background check.
Dating a new person? Background check.
Selling a car? Background check.
After all, no one who has nothing to hide would object, right?
If it jams, force it. If it breaks, it needed replacing anyway.