The true rule zero, I don't know what it is but I bet it is between -1.2 and pi(mmmmm pie)
I think there is also a slippery slope with ultra realism. If you change one little aspect to the most exacting detail does that mean everything else has follow it. It could seem sort of weird to some people to have one rule trying to be a simulation of real life, and an another where the dm decides "this happens just because it does". You don't want it to devolve into situations where your rollings to see it your cart accidently gets hit by a meteorite while traveling the countryside.
I think there is also a slippery slope with ultra realism. If you change one little aspect to the most exacting detail does that mean everything else has follow it. It could seem sort of weird to some people to have one rule trying to be a simulation of real life, and an another where the dm decides "this happens just because it does". You don't want it to devolve into situations where your rollings to see it your cart accidently gets hit by a meteorite while traveling the countryside.