This has been suggested many times, but Bytro seems to think very little of this topic

Send some rockets after the enemy captures it, works about the same way.

Well, if this happened then somebody could send a few ACs behind enemy lines, take a bunch of enemy cities (but not hold them,) destroy the ICs in those provinces, and then just leave the entire enemy nation's economy crippled. While I'm not opposed to doing this to other players, the thought of it happening to me is frightening at best.|

Worse than this happening to just one player, though, is if two player do it to each other, and then neither side can produce anything, forcing them to wait to either get the resources to rebuild their ICs, or just get steamrolled by the one lucky player that didn't get destroyed by this strategy.

No thanks, I think I'll pass on this one.