In reply to jwi:
It's a hard ethic to get my British/Scandinavia head around - not quite sure why two holes are better than one. But then in the UK we insist of leaving numerous rusting pegs and nuts tied together with rotted hanks of rope for abseil stations, rather than two nice neat bolts, and that doesn't make a lot sense either!
Having broken a drill bit drilling soft wood on sunday, I can imagine flying off with a drill in your hand means going through rather a lot of drill bits!