There's at least one in every crowd, kids. Get your Rick Ryan Brand (tm) Stun Gun for only $58.95, and watch these potential equipment crashers run in terror! For only 158.95, you can upgrade to the Tesla Coil 2000 model (pat. pend.)...
Eh, the taser I have is $20. The thing to do is to not just stand behind your table until somebody comes crashing into it. I always walk out in front and stand there then politely suggest they move back.