If it's winter, they tape them to anything outside and leave them in the cold.
If it's summer, they tape them to a tree and cover them in peanut butter and leave them for the bears.
If the rival spy is particualrly unlucky they will indeeed get taped to a post in the middle of a red light district and left for the cougars.... being mauled by cougars is a nasty, nasty end....
(If you have no idea what I'm talking about, google "Canadian bar cougar" or similar. One of the most fearsom weapons this nation has... )