My friend lives in North Wildwood, he lives in a multi unit prop

Cape May - My friend lives in North Wildwood, he lives in a multi unit property with several mailboxes. As we were leaving his house he said let me check my mailbox, he pulls his mail out and everyone's mail was in his box. Now what if mail in ballots were delivered that day, he could have taken them and filled them out for the candidate of his choice and mailed them off. How often does this happen, and not just hear, I live offshore and occasionally get a neighbor's mail, this is not the way our elections should be decided, we should have ID and vote in person.