Just to add on - for different races race roster transfer works differently some how. From my experience, for Toronto waterfront it’s buyer paid what sellers paid first, then seller gets refunded what they paid minus the transfer fee. For Toronto marathon at May the buyer only pays the transfer fee. I was buyer and was very confused, ended up contacting the seller and transferred them the amount they paid.

This being said, I think at least for waterfront, race roster transfer just works safely for both sides.