I have no idea what you're all going on about, but...
Rogue sees a cop on the chat-list, drunks some rum and goes looking for him... no problem. Point being, faction tags or other clues in the call-sign are reasonable means for targeting somebody. On the other hand; a mercenary hunts for a ship he's never before encountered and has absolutely no insight into so far as RP goes (and no bounty declared), but knows it's a particular player... that's meta-gaming and could be covered as per the respective rule.
For example, on Rogue chat on Skype...
“Just wondering... who's that level-90 guy in Cortez?”
“Oh, that's Joe Bloggs and he's hauling base stuff to GRN.”
“Well, I have a BAF ship handy nearby so I'll go blow him up!”
