It's 90% user error. If people would learn not to pump the tap BEFORE filling their cup there wouldn't be as many problems. I find myself seeing that all the time - people walk up to a keg and before they do anything they start pumping it.
Then they are all surprised they get a cup full of foam. Fill first, then if needed (and ONLY if needed) give it a pump or two.
Geez, I was the only one paying attention in college?
It's a bummer too because Keg beer tastes soooo good.