That’s how my dad raised me and the rule I always followed and taught my kids. But I was amazed at how many parents did not follow those rules when I was raising my kids. You’ve got to be sure that the dropee has his/her key, after all.
When I became a parent, I was shocked at how so many parents abrogated their roles completely. It hasn’t gotten any better as the kids age. It just makes me tighten the reins on my friends’ kids because someone needs to step up.