The simple fix for spawn trapping (which by the developers defenition IS boosting and exploiting an in game mechanic) is to have it where if a team is instantly spawning and dieing, then they spawn DIRECTLY behind the team which is doing the trapping.
Imagine a line on both sides of the map about 2/3 of the way across into the enemy spawn. If 3 or more enemies cross this line, then the other players randomly spawn across the map. This would stop all the poor sad little souls that have to use this to boost their in game penis and show their boyfriends how "good" they are.
And before anyone says "spawn trapping isn't an exploit" here is a DIRECT QUOTE from Treyarchs online code of conduct
Boosting
Users who organize to exploit the game for the explicit purpose of ranking up very quickly or to appear in a high position on the leaderboards.
• Minor offense: Temp ban, complete stats reset, leaderboard entries removed once
• Major offense: Temp ban, complete stats reset, permanent ban from appearing on the leaderboards
• Extreme or repeat offenses: Permaban from playing the game online
Glitching
Users who go out of their way to exploit the game to grief other players. An example would be going outside of the map’s clearly defined playable boundary.
• Minor offense: Temp ban from playing the game online
• Major offense: Extended temp ban from playing the game online
• Extreme or repeat offenses: Permaban from playing the game online
Now let's break this down REALLY EASY so even the simple mided people who do this can understand
"Users who organize to exploit the game for the explicit purpose of ranking up very quickly or to appear in a high position on the leaderboards."
When a team spawn traps, they are EXPLOITING the spawn system at the expense of the other team and NOT doing the objective to rank quickly and get higher on the leaderboards.
Now part 2
"Users who go out of their way to exploit the game to grief other players."
This is also EXACTLY what these "teams" or "clans" do. They intentionally go into the game knowing they are going to do their best to spawn trap the other team just for fun "griefing" the other team. Again they are exploiting a flaw in the static spawn system
Here is the link to the complete rundown of the policies.
http://community.callofduty.com/message/106042032#106042032