Making one side smoking and the other not won't work from the companies point of view. I really don't think they would sell enough on the smoking side and then you would get non-smokers complaining because they are forced to book on the smoking side.
I assume as on other lines, you would have to call security or the front desk to complain. The problem will be - will they send someone soon enough to "catch" the culprit. I don't know how much the room stewards will help as their gratuities are depending on the cruiser and if they blow the cruiser in, good bye gratuities.
A camera taking a picture around the divider might work.
As for in Europe, Europeans smoke so much more than North Americans and I don't see the rules being the same because of it.
For the cruises out of Asia, there will be not be any no-smoking rules. The Asians are big time smokers and will not be giving that up anytime soon.
I thought I posted the new policy. I'll re-check that.