Stupid contributors.
Put a cabin crew member into the flight deck each time one of the pilots needs to visit the toilet....brilliant!
What exactly would the hostie do if the naughty pilot decides to divert? Take over control? Overpower the pilot and force him/her to behave? Threaten the pilot with the fire axe? Open the door to allow access to the other pilot?
Anyone who flies will know that they can do what they wish with regard to single-pilot operation. Thanks to the locked door policy, this is easy.
And what if the pilot decides to commit suicide and promptly shuts down the engines and stuffs the nose down? Just what would our heroic flight attendant do? This has been done with both one and with two pilots present.
Grow up, panic-stricken spotters.