You referred to BYO. In my parlance (and in the context you wrote it) that means B(ring) Y(our) O(wn) alcohol. I would want to avoid anyone not familiar with the law here that buying booze off the shelf is easy. Its not. Hence my reply.
Thanks for the info re purchasing alcohol BTW, I was aware of the difficulty from previous trips not that I often purchase when travelling. In the BYO context I was inferring to duty free, which ironically the UAE has one of the most generous limits around compared to many countries where alcohol is common place and easier to buy.