A lot of it depends on when/where you’re surfing, I think. Lets face it… like it or not, there are “longboard days” and “shortboard days.” If you go out at a spot dominated by shortboards, that’s a performance wave, on a head high or overhead day that’s not really suited for longboarding, you’re gonna get some looks. And if you’re trying to shortboard at what I call a longboard wave spot, you’re gonna get frustrated really quickly by all the longboarders sitting outside and getting the long rides. My experience has been that that’s how “longboarders” get a bad rap… either by frustrated shortboarders who choose not to ride longboards when the waves call for one, or by longboarders who are out in conditions that are not really appropriate for their equipment, and their performance shows that clearly. So for me, more equipment choices means more fun, and more days maximizing the potential of the waves that day.
That aside, bad etiquitte is bad etiquette, regardless of what you ride.