As the others have said, visual image is a pretty minor consideration, but it's still worth considering, if only briefly.

Like Rockonn and Holly said, you could lull them into a false sense of security by dressing in suits, as ska kids or in the full-on rap-star attire - just don't wear black hoodies and cargos, or people will think you're Limp Bizkit :eek:.

But whatever you do, don't agonise over fitting in with the market thrash metal image, or try too hard to look like one of your favourite bands; just do what feels natural.