The situation you described tazuras, might be a problem. But I can think of situations, where this might be necessary.
1. OOC? I wait outside a guard system and I adress a pm to a player inside the guard system to ask for free access to this system.
2. How does a bounty hunter hunt down a ship, without knowing where it is?
3. How do you trap a smuggler, if you don`t know his current route and location?
4. If I look for an escort, I have to send a message to other players. If I actually had to meet the escort before I could talk to him, I would never be able to find one.
Edit:
5. If I am 30k away from Manhatten with a cardamine load and I need a scout to check the docking trafiic, would it be out of character to adress a player in this system? Do I have to meet someone and risk to get caught?