Hmmm.... music to make them leave you alone...
Well, some of my favorite "noodlings" to keep people away or make them think I'm a much better bassist than I reall am:
-Sliding harmonics... on a fretted bass
-"______________" (insert Primus tune here)
-Obnoxious high speed funk bass. Toss in "avove the nut" rakes for best results
-repeatedly bend the piss out of tapped or artificial harmonics
-try and figure out which note is going to make [u]every[/u] acoustic guitar in the place resonate (open "A" is a good place to start)
-the Ozzy/ Primus version of "NIB" is usually good for a "turn it down!"
-Ask to try out the 1,200 watt Sun Head into 2 4x12 cabs then tweak the graphic eq for 45 minutes. Observe to the employees that you only wish you could turn it up to where the tubes start to work their magic.

Just a side note, many guitar shop types are infuriated by the idea of a bassist who's faster/better than they are. Use this to it's full potential my friends.