K, well, actually...
Say a LN pilot wins against an HF in NY.
Later, that same HF is attacking in say...VA...(which is allowed)
The LN can reingage, because he won.
Whenever a trader is pirated, and refuses to pay, he either flees, or dies. The pirate wins, and can reingage. Traders would never start a combat(unless you're me, and have a pair/trio/foursome of ace pilots following you around cause they love you.)