I am taking Eddie to the vet to see if there is a medical reason for this...it is sudden aggression that isn't characteristic of him. He does have an injured leg that while it is better, could still be hurting him.
I don't care about this hype about dogs doing their "jobs." It is not a job to bite anyone unless they're breaking into your house or attacking you. Well socialized dogs learn what is normal and acceptable and what happens in the regular course of things. And the things they are not socialized to are foreign and usually scary to them and that's why they act "aggressive"...usually out of fear, with some on the offensive.
I agree. However, the waving of the clipboard was a perceived threat. Dogs can't tell the difference between a real threat and a perceived threat. There's a reason a helper goes through certain behaviors to turn a dog on or off.
Without having been there, it's impossible to know how the incident started. Eddie may have been going over to say hello, tail wagging, tongue hanging out, maybe some barking out of excitement. Then the UPS guy who sees a charging dog and doesn't know how to read dogs gets worried and waves a clipboard. Eddie takes that as a threat and becomes defensive.
I agree that you should have more strangers over and teach him what is acceptable. If he approached out of excitement to meet a new person, you have less to worry about, but it's still unacceptable. Not everyone can read dogs, not everyone wants a dog to come over and meet them, and delivery people may be quick to assume they're going to get bitten.
The scenario with the drunk people shows that Eddie will act proactively to protect you. He didn't make any attempt to bite, which is good (maybe).