I was always under the impression that Magnesium uptake was inhibited by Calcium. I could be wrong though.
I take a ZMA supplement every night before bed and it does help. Well, my dreams are much more dramatic and weird, which is a reported side effect of ZMA, so I am assuming that it is working as described. However, I don't eat anything with high amounts of calcium for about 3 hours before bed due to what I said at the top.
People too weak to follow their own dreams will always try to discourage others.