But base commissions are literally a thing. People buy base commissions because the artist is better than the buyer at using bases, and wants to see their character in the mlp style, not the artists style.
It's not really scamming when the people who ask for a commission know what they are receiving and know that using a base is how they are gonna get the art, but just with a character on it. They consciencly decided to ask for a commission so that's what their gonna get.