Well, it was a constraint I saw in `Boost.Random`, and thought: "Hang on, that's never going to ..." before realizing that I couldn't guarantee it.  I think that the closed lower bound is a much safer bet, simply because zero is a typical closed lower bound of just about every uniform RNG I can think of.

I'd feel happier having it, and giving the guarantees we can offer.  OTOH we could always just put in an assert, and see if it ever triggers for anyone. :-P