As a Provider on Thumbtack, I am very reluctant to accept a direct lead that would charge me more than $5 upfront regardless if whether I'm chosen or not. I would be more inclined to accept the offer if I knew the fee would be waived - should the client decide not to use me. Your policy regarding billing the Provider upfront, whether they're hired or not is very lopsided, unfair, and a deterrent for Providers using Thumbtack. Who likes paying something for nothing - especially for leads that have no guarantees, and has the Pro in the thankless position of being left literally "holding the bag?"
*Title edited by moderator for clarity