As heels have become higher, the toe over hang has become more of an issue. A half size larger will not always correct the problem as it could make the shoe ill-fitting all over.
I do not think this is a case of wearing a shoe that is too small. I think it's a design flaw. The pitch of the shoe causes the foot to slide forward. The tip of the shoe is often times too tapered to accommodate more than 2 toes.
When it comes to pumps, frequently I see women wearing them too big as there is a space between their heel and the back of the shoe.