Wrecking a perfectly good prize? Cannot think of rule to prevent it, or a reason to do it. Gunnery practice?
Julie and I were pitted against one another in this quandary with I the one who wished to blow-up the abandoned ship. The story goes something like this:
I had just finished killing off David (a teammate of Julie's) in a melee attack wherein our ships were grappled together. I had lost many men in my attempt to take the enemy vessel and had greatly damaged her hull in the process. Thus I had taken over greatly crippled ship with a very small and tired crew. Meanwhile, Julie was approaching with a solid ship and nary a crew lost. Knowing that I could not win another melee attack, survive a fire-fight, or outrun my enemy, I chose to abandon and blow-up my prize rather than to allow it to fall into the hands of my enemy once more.