its a matter of perception - - being grouped with a capital warship that is not in sight or on the scanners should not be a problem.
after all, - as a BHG, i can group with the BHG core that are currently raiding minor while i am in shigoku. - that doesn t mean that i am participating in the raid just cause i m grouped.
but being in sight - is troublesome. - assisting the pirating character in ANY way ( that also includes verbal assistance or fighting off police / military players that "might" head to the traders assistance ) is not working. a trader is SAFE from a capital warship, period.
that is a rule - that has nothing to do with roleplay, it is a rule. so if a destroyer sits there and simply defends the pirate in his little bomber from maybe NPCs - it is STILL interfering with the piracy event. if a warship even only intimidates "would be assistance" to not assist - it is interference.
when the capital warship acts as a shield against the traders guns while the pirate in question makes his demands - it is also affecting the piracy.
best to stay away from any piracy when you re in a warship. - that is a rule like "best never to engage your cruise engines unless you have the intention to RETREAT and LEAVE the system - when in a pvp".
Tho only allowable and realistic situation i could allow of pirating in a dessie is if a ship like that were stationed at a single position over the long term to institute a toll or tax. But even this must be done with extremely good RP chatting skills to pass in my books. Simply put, a destroyer was never meant to do the dirty work of bombers and fighters. It's a warship, so keep it for wars and homeland security.