I used to work in an off licence (Liquoer store); and I never had any trouble selling those items. If people have yet to hear the gospel in its true restored form they genuinely believe that they are doing nothing wrong; therefore I don't believe it is right to refuse to sell products such as these. Although I was not a member at this time I was already beginning to question my faith; and it wasn't much longer after that when I started teachings from the missionaries.
Certainly in the UK it would severely restrict where one worked. Supermarkets, news agents, off licences, convienience stores, petrol stations, restraunts and even some video rental stores etc. would be included in some of the places than a latter day saint would be unable to work due to refusing to sell tobacco and alcohol.
I think that due to the current financial state of the world as it is at the moment and the difficulty in getting a stable job (certainly in my country) that if I got a job in one of the afforementioned establishments that I would definately take it.
As I said; those who are purchasing tobacco and alcohol products have yet to hear and accept the true restored gospel, and until such a time as they are ready to do so we would be wrong to refuse sales to them based on our personal beliefs. Everyone has the right to believe what they wish to believe.
That is my view upon it any how..