If they allow customization, should it be able to be copied by other players/ factions?
I know more than few people if they go to the effort of making their own emblems/designs, probably would not 20-200 people copying it. It would allow for a sense of individuality. Same goes with factions, if you go to the effort of making a succesfull faction you don't want players pretending to be a part of it, possibly ruining your groups reputation.
On the other hand, being able to run false flag operations so to speak could add an interesting aspect to the game. That, and somtimes you see a great design and would like to be able to use it as well.