Actually, Claudia only got noticed because of her habit of spending time around Gabriel. They've been careful to try to keep Crowley from getting too much info about her actual job.

"Once he was done being glad to be alive again and sorting through his baggage you mean?" Gabriel asks drily. "He managed to keep complaining to a minimum. It really helps that I don't expect him to be 'on duty', so to speak 24/7. When she's actually with me, what he's gonna do that an archangel can't? And since we cant get in the Warehouse, not much point in him hanging around outside."