I think the best thing to do is just be honest, regardless of anything.

But it is important to remember that a seller's rating is their livelyhood and it can greatly effect their standing on the site.

I think most buyers go for price, but will preference a top-rated-seller or well-known seller that they trust, and a good rating adds to that appeal.

I only add a rating once I've recieved and inspected the item, and even when I get on the site to leave my score I'll double-check the listing to make sure.

I always keep in mind that postage issues can be a local problem (Australia post for me) and that international postage can carry risks and delays.