It is not only that but also the intelligence risk. Lots of small electronic devices can be hidden inside cellphones and key fobs. Everything from hidden USB drives, audio recording, GPS tracking, video taping, and photos and more. A modern smartphone already carries many of these features. Foreign intel and terrorists would exploit this information.
Nonsense.
Have you seen the size of your average US embassy ? Its not like the one room Ecuadorean palace where Mr Assange is hanging out.
I'm no expert, but I would hazard a guess that the secret squirrel stuff the US do in their embassies is in a separate part of the building well away from un-vetted eyes, no doubt also served by a different entrance. Hell, its probably in a different building altogether !
Sounds like someone has been watching too many Hollywood movies.