Our Son Is A Christmas Double Agent

Ah the secrets. The secrets get pretty heavy at Christmas, especially for the kids who end up going shopping with mom or dad.
Today, both my wife and myself grabbed our 3-year old and took him out to shop for the other parent. Both times he came home saying, mom/dad said not to say where we went or what was bought and it was a secret.
My son the double agent. He knows too much.
The mean thing to do would be to interrogate him. He would fold in 30 seconds. But that is no fun. I did not ask, I did not bring it up, nor will I.
Same goes for my wife. At least the boy keeps secrets now. Before when we have tried this, he would run in the door yelling just what I had told him not to say.
So there is progression. He is learning the tricks. It was so much easier when he was a baby and you could tell him anything and he was the ultimate vault.