this has happend to me a couple of times in the past 2 or 3 months...
its been a known fact that some sticky stuff like paint or glue gets the gauge stuck..
it requires u to disassemble your gauge cluster to clean it up...
but in my case.. its a rare occasion this happens so I dont think its worth my time to attempt to fix the issue.. when a simple ignition off\on solves the problem =)
now if the gas gauge just all of a sudden read empty in the middle of a trip I would be concerned. or if it stoped working all together