AngraRULES
Member
That's what the local bands are for! Hurray for pre-sale tix! XD
8 out of 10 times, local bands help people by providing them time to grab a bite to eat before the main bands. Not to mention that most people get tickets from the opener bands simply to avoid the ticketmaster fees, not necessarily because they wanna catch the openers.
I don't think local bands really contribute to the public outcome of a show. If anything, a show with too many openers is more likely to have lower attendance than otherwise.