You don't need to know people personally to trust a signature, you just need to know that the organizations they're coming from are at least somewhat reputable.

You don't need to know people personally to trust a signature, you just need to know that the organizations they're coming from are at least somewhat reputable. Ideally, signatures should all chain up to the root of trust in your package manager, which is presumably operated by some entity that you've decided to place some trust in.