No and no. Players can't create an assist call. This is why it is protestable because it is a mis-application of a rule.
There is a thread on here, I think, that discusses whether a balk is a judgment call or rule interp. It can be either, depending on what was called.
In your OP there is no question on either side of the equation whether the runner was assisted. The question is was the assist illegal or not. That is protestable.