My Mom used to do the same thing at Christmas and birthdays. It was always fun trying to figure out what it was inside the box.
I was told at the post office once that you couldn't use boxes like that and if you did, they had to be wrapped with brown paper. It is good to know you can use other kinds of boxes and recycle them instead of trashing them. Sometimes it is a challenge to find a box and I really don't like having to pay for them at Walmart or places.