No i think is ok for customer too, when somebody start to get a good reputation and become a trusted it's quite common they get some privilegies.

If you are worried about people getting a good reputation and then pulling off a big scam i don't think we have to worry about it. Reputation will work hand to hand to the money the seller receive, so you cannot sell 100 items for a total value 100$ whiteout any issue and then expect to sell an airplane for 1 million dollars and get the fund released immediately