It's not trivial, but it's very, very feasible. Consider that Amazon already does a lot of manual review. They do manual review of individual transactions if a

It's not trivial, but it's very, very feasible. Consider that Amazon already does a lot of manual review. They do manual review of individual transactions if a customer is unhappy. The scale of that is enormous compared to this. They also already do some manual review of product listings. (Every product listing page has a "Report incorrect product information" link.) Adding this kind of manual review is surely a drop in the bucket if labor costs are the issue.