Children's presents, not adults although it could apply to both.
If you have known someone years and know when their birthday is would you consider it a good thing that they always give the present late as it "extends the birthday experience", or would you consider it rude?
Just to be very clear, presents are in no way expected, and are gratefully received even when 3 months late.
I think it's nice to receive a present at any time but unfair on a child that thinks the person has forgotten them especially if siblings have all had a present (also late by a week or so but not months).