WRT hands near brakes I'd imagine that's the problem with any bar ends though...
I ride in London and only move to the bar ends when I'm settled into a long-ish stint - i.e through a park or on a road between lights and with no crossing points.
If I'm weaving through traffic or suspect that someone might step out, then I'm on the normal bars covering the brakes.
Actually, now the subject has come up, I use mine far less than I used to on my old bike (Dahon Matrix). I think Bromptons are so un-aerodynamic that I now tuck my arms in and use the gear levers to hold on to. My not having my hands stuck out on the bar ends, it does make a noticeable difference to effort v speed.
WRT them hitting the ground, if it's really close, then surely a slight adjustment to the angle would work. Failing that, taking a few mm off with a hacksaw would also do the trick.