What about the (unlikely) case that a wallet is shared between 2 or more individuals? Could I then "share" my private key with a trusted person (e.g. a parent)

What about the (unlikely) case that a wallet is shared between 2 or more individuals? Could I then "share" my private key with a trusted person (e.g. a parent) and claim _not_ to have complete dominion over the gains, thus no gross income?