Why do drugstores make the sick walk to back

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and then you have the people buying cigarettes up front?. Im not to sure about this, i have never smoked in my life and i hope to never as it seems to be ruining lifes alot quicker. Today is my Granmothers last day with us and she used to smoke and they are saying her lungs are like leather and just nothing left of them. So some healthy people walk to the back of the pharmacy like myself and get my prescription but the smokers can stay up front and buy there cigarettes and it just doesnt make any sense to me.