I think its important to note that there are big cultural differences and european countries do generally have a more acceptance of alcohol drinking at a lower age - however alcohol problems in those countries are often higher, although more accepted as it may be that they drink all day long, but with meals (IYKWIM?). It is still an alcohol problem, though.

I think that perhaps when the child is older say 16 or 17 and you are aware that they will be drinking anyway, it might be wise to have them drink it in the safety of your home, but I dont think that means that a parent should go as far as purchasing the alcohol for them. I also dont think you should allow other people's children drink, regardless.