> Would it have upset you if they were asking for any review at all, instead of requiring a 5 star one?

That has largely the same result. Most satisfied customers don't bother to leave a review, so real reviews tend to skew towards people who have had issues.

If you bribe satisfied customers into leaving a review then your reviews are no longer from the same sampling population as your competitors' reviews and you end up looking better than you really are by comparison. Plus, if the incentive isn't offered to everyone then people who get it (and then are disproportionately likely to leave a review) will tend to like the seller more because they liked receiving the incentive.

It would only be fair if the same incentive was provided to all buyers for leaving reviews of all sellers.

"Asking for a friend," right?