problem with that is that troops can't kill spies. i guess the towers will kill them defensively, but imho spy defense towers should be used only by people that osw frequently who also have a lot of gold invested in allies.
@Wordwaster-With like 500k spy atk you can still sct most builds and the towers make you hard to ko with asns. High plunder and a hard ko.
That was ee, but i agree with osw. Alot of towers arent needed if you have less then a few.hundro bil in allies.