[mumblypeg]

...background check.

Yep.

[sport]

It won't do any good. The operative will already have documents prepared that will confirm that he or she are as they purport to be.

The best defense is to never forget two things: 1. Loose lips sink ships, or my ass. 2. The only sure way two people can keep a secret is that if one of them is dead. And as a bonus: Even a fish would not get caught if he kept his mouth shut. That one, however is not foolproof, there are nets and seines. But it does cut down the odds considerably.