[NutmegCarrera]

Rick-
A couple of points:
1. The FIRST complaint may come from Activision - as you're using one of their product's names (Guitar Hero). That may be as problematic as anything related to Fender or Vox.
2. Mark Henry brings up a good point. Although my experience is more in the line of patents, rather than trademarks - you do get somewhat of a "gimme" for whatever your gaffe is until you get a letter, be it from Vox, Fender, Activision, etc... Once you received the letter, if you do not take corrective action - then you can be held liable for damages if you do not remedy the situation. In your case, taking down any posted fliers is probably the remedy.

I'm not a lawyer, but have seen these sorts of things happen. Manufacturers of hygeinic products (that are made at an alarming rate) tend to patent their products to the hilt. If you fly in the face of owners of such I.P., and you willingly continue to infringe - the courts do not tend to be freindly.