PSA/BGS Graders grading their own cards?

[nameanking]

Is there certain guidelines for these people? Can they grade their own cards? Or a friends/ coworkers cards?

[KJCBALLER]

Technically they cannot even be in the hobby buying/selling/trading cards. This is my understanding with BGS at least. Not saying they all does this, I just know that those are some guidelines if you are going to work for them.