Rule wise, the fighter can't enter that system or engage that trader for 4 hours.
Which reminds me of something.
With the new purpose of traders, which is keeping player bases supplied. I think the 4 hours rule should be applied to them too, as 5000 units of H-Fuel can change a lot nowadays, and not only that player's wallet.
EDIT: Actually hold on, gonna ask in rules section 8|