I always thought having a hostie relieve you on the flightdeck was one of the perks of the job ?
On a more serious note, I assume that you have to join the queue of pax waiting for said cubicle which could mean being off the flightdeck and "vulnerable" for some considerable time.
Post 9/11 how do airlines view this, do they see it as a major risk ?
Oh for the days when the pilots would chat to the pax on the way to spending that penny and invite you up front for a look round.