IMHO, sanctioning balcony smoking would be difficult to implement at best, as well as appearing to flip-flop on stated policy if it did ("we're a 100% smoke-free hotel, but we allow people to smoke on room balconies"). Because of the HVAC system in many Marriott properties, they likely would need to designate rooms with balconies on certain side(s) of the building as smoking-permitted balconies and rooms on other side(s) as non-smoking balconies. Then the reservation system would need to be adjusted to allow people to reserve either rooms with smoking or non-smoking balconies, since some people seek out rooms with balconies to be able to enjoy fresh air (in locales which have it ). Finally, since the air system used in many properties often pulls in external air, the res system would also need to permit people to select rooms away from smoking balconies. (I know some smokers who cannot detect smoke that was pulled in by the air system, but for those with smoke/dust allergies, it can be extremely potent.) Since those changes could significantly curtail flexibility in room assignments as well as call into question whether it stands behind its stated policy, it would surprise me to see Marriott officially sanction balcony smoking at its properties in the US and Canada (and other areas where the "100% smoke free" policy is in effect).