It will destroy your plunder. Build all guilds (with one atk bldg) until you have AT LEAST 40 lands. Then, save enough to convert all of your LL's to L3 SoS's and all of your HL's to L1 Vol's. Do the conversion all at once. That is the fastest way to grow a hanse
I skim my spies so the plunder from attack doesn't affect me too much, I just wanted to know if it'll get me better gold for assassination