While I haven't tried it to confirm, all US model MBs will not allow the windows to work without the key on.
Unless the law has changed I know this to be a fact as it was one of the things that had to be converted to DOT spec when we were bringing in grey market cars in the early eighties.
Another interesting sidebar is that when my short wife bought her new ML in late 98 one of my biggest gripes was that the seats DID NOT move with the door open key off. The real interesting thing is that this is programmable in the AAM (all activities module), BUT it is specificaly stated in the WIS (workshop information system) that cars in the US can not be programmed that way.
Because I am 6'4" I have programmed mine anyway, but I must be certain that if kids are left around the unlocked car that they don't strangle one another with the windows.
Bosch Master, ASE Master, L1
33 years MB technician