If I understand the math at all (and it is quite possible I don't!), the odds against the above producing a duplicated ID at any one choice are something like: 0.000000000000000000054

Which, when compared with your odds of being hit by falling space debris: 0.0000000000000166

Or getting struck by lightning: 0.000001763

Or that you would be one of those caught up in the recent tsunami: 0.000008333

Seem pretty good odds to me.