I guess I'll bite because there are many situations where it's an issue.
You attack a player running missions to mess with your BGS, he logs and you can't prevent the missions from being carried out.
Same could be said about powerplay, or a Pirate attempting to acquire cargo from a target.
Perhaps you are trying to kill a notorious ganker, they decide to clog and avoid the rebuy. That's no good because he never recieves any sort of opposition and continues on a mad ganking spree.
The main issue is you pull someone and they clog on you because of a "Unwanted PvP situation". To which I say, if you don't want PvP, don't fly in open play. It's that simple.
What is the old saying? If you can't handle the heat, get out of the kitchen?
To which I say, If you can't handle PvP, get out of Open play.