From The Sunday Mail (Brisbane Australia) this weekend.

Teenager and his dad went to a hardware store last weekend to pick up some
timber. They loaded up the car and when Dad went to pay he realised he'd
left his wallet at home. So he left the son at the store as security while
he went home and got the money. On his return the assistant said "You must
really love your son to come back" To which Dad replied "Nah, he's got my
tape measure!"

Mekon