There are locations on certain airports where being single engine can make for a difficult time maneuvering, or can make it "unsafe" for others such as F14 in ORD, where you get the short push and have to do an about face to leave the gate, i've seen plenty of passengers nearly get knocked over from guys leaving there single engine and revving it up to god knows where just to make the turn.

Not arguing for it or against it, but what it comes down to is the captain's decision. When you're the captain, it'll be your airplane to decide what to do with it, as you see fit.