I think I remember reading that our signalling control system is considerably simpler than that of many bikes. Our single turn-signal indicator light electrically bridges the left and right sides of the bike since it's only one light. In a system that had separate blinker indicators for left/right, I don't think it'd be a problem. That and I bet they designed the lights/advertising materials from the standpoint of this being the first light mod in an otherwise stock bike.
I agree that perhaps they need to revise the advertising materials a bit. But hey, at least we've got a community of people to put our collective heads together, figure this stuff out and make it a non-issue
