small sidewall tires are leaving the wheel more prone to damage whether it's a stretch or not. a stretched tire likely has an even stiffer sidewall because of the stretch.

depends on the pothole, the speed, and just luck sometimes. i've managed to hit a few nasty potholes and come out unscathed, though i've had friends kill a wheel in a pothole that isn't even that bad, but they hit it just 'right'.

i can dig a mild stretch sometimes. as with any decent trend/fad, it's always ruined by some people taking it too far (and consequently thinking it's actually cooler to be more extreme).