Don't they wonder why granny , aunt X and cousin Y give them gifts but NOT their parents?
When I was young , Santa filled the stocking and left s present or two but we also got a couple of gifts from our parents. This is the route we've taken with our kids cos it makes the most sense, I reckon.
However 2 of our good friends' kids believe that EVERYTHING is from him, ie nothing is from their parents. I know for sure that my very curious DS1 would wonder why our next door neighbour gives him something but NOT his own parents. Not in a grabby/entitled way, just that he wouldn't really understand why.
I wish there was a standard role that Santa played so it was easier for us all to cover our tracks!!