Traders shouldn't be able to avoid interaction that easily as they can at the moment; they are the very beginning of activity.
Pirates, on the other hand, are much fewer in numbers than ganking navies, bunters, police forces, escorts etc. They should see coming angry lawful capgank from long distance, retreat to some deeper system and hit the lanes in other part of the House/terrains around it. If there's big probability they'll get caught and ganked to hell any time they pirate lanes, that's bad, and sadly that's how it is now - I intensively play pirates for few months now and it's hard, no wonder why people don't want to do that.
