Interesting post Urika! I have the exact same situation and wondered about it from time to time myself. My cousins dog, scrappy, is 1 yr. old and completely untrained. Scrappy, jumps, licks and nips all at once

and my cousin has done little to stop it. But I found it horribly annoying and give the "off" command every chance I get as the owners at least allow that.
Hercules makes sure she stops. He playfully grabs her back legs etc. so she must focus her attention on him and not me. He never does it if the other dogs are simply looking for attention, just to little ole scrappy if she's jumping on me!
I never thought of it as a potential dominance issue, but glad Judi W replied it really is more of a pack thing than a dominance thing.