Or just kill them. Infiltrators are worth a lot of money, the h/p cost is nothing compared to the investment an infiltrator takes. Plus you're more likely to deter infiltrator attacks if you punish them ruthlessly.
There are plenty of reasons where that is not the desirable solution, say when you got a Prisoner Agreement with the enemy Realm protecting your own Infiltrators. IF you deport them, I always thought sending them to the Colonies was the worst idea, in all honesty.
