I while back I set up a rule on my mail server that would effectively OOF respond if people in my company if they didn't CC my manager (indicating that you should CC my manager so that he can triage whatever issue you may need me for). People started coming to me with real issues (instead of the "reflex ask the senior engineer") with valuable evidence (logs, etc.) - they not only needed to convince me to use my time on their work, but my manager as well. Some even found their answers on Google (I was in complete shock). That extra barrier (my manager) was an excellent deterrent for people pawning their work off on to me.

I have since turned it off, but people remain a lot more respectful of my time (I may now be perceived as a dick because of it).