IMO, if you're sticking your gun around a corner off your shoulder, not looking down sights, barrel, or even seemingly close to shooting remotely like a paintballer, I'd consider that blind fire.
I mean, if seeing where bb's go is enough of a requirement to certify "x" action as not blind firing, I'll be the first to get one of those 90 degree angle mirror things and shoot around corners w/ that.
Hell, with all the cheap camcorders on the market, I can make something like a cornershot. Which raises another related and interesting question, would a cornershot, or using an assisted viewing device mounted on an airsoft gun to shoot around corners from cover count as blind firing?
Are we after the literal interpretation of the the rule, where as long as you can see where your bb's go, its ok? Or do we enforce the spirit of the rule pertaining to blind firing?
Just your friendly neighborhood narcissist gearwhore.