I wouldn't run only a single taillight because I've had them fall off or batteries go dead during rides. Personally, I use 3 taillights while commuting. One is on my helmet, one on my rear rack, and the other attached to the left seat stay. My rack light is non-flashing, and the other two pulsing.

Five or more taillights are more than I would want to deal with, particularly charging all of the batteries, but turning them all on and off would also be a hassle.