The only possible reason for a "spy" that I could think of would be to find out tactics, etc.
Is there a team that plays that serious in Phoenix?
I have found some websites for teams that are pretty serious about their airsoft.
For instance, one team in Canada had a pictures of themselves (so they say) doing room breaches via rappelling. They would accept all challenges with one requirement, the winning team won the weapons of the losing team.
Now that is some serious airsoft.