You mean hide your own from other people? Or hide all the FC names of other characters on your screen?

For the former, I wouldn't use it, but an option would seem ok.

For the later, I agree. I'd actually like if it gave us a set of three options for displaying Free Company names:
Show them for everyone
Show them only for members of my own FC
Don't show them for anyone

I like knowing when someone I see is in my FC, but if they're not, then what FC they are in just isn't of much interest to me (and certainly not worth all the screen clutter it causes).