fair point! We believe "Require approval for all external contributors" should be a default setting, as you cannot trust anyone who is not a member of the organization
If companies can screw you over and claim it's a mistake, there isn't much a person can do.
It's all about level's of trust, a maintainer going rogue is less likely, a past contributor going rogue more likely but not too much, a stranger with a typo pr merged even more likely but still, a complete stranger least trust worthy.