^^^ What solidgold2 said.
I am an honest seller but I don't offer returns. Why? Because every single listing has between 10-16 photos on it, my photos are crystal clear, and my description is detailed to the point of boring people with the details! I answer every question promptly, most within an hour, and obviously I ONLY sell authentic.
I don't offer returns because 1) some of my items are consignments, 2) I don't trust people to send back the same thing they received, seller's mark or not, and 3) even if they send it back, it is never in the condition in which it was sent.
That being said, I am a very reasonable person and if there is truly some issue with the purchase, I will do my best to work it out with the buyer.
Anyway. Sorry if this is not answering your original question directly!!
For me, the most important things about selling on eBay safely include:
1) loads and loads of clear photos of all angles of the bag and any identifying marks of authenticity
2) adding a seller's mark somewhere invisible on the bag OR a tyvek tag
3) stating the provenance of the bag if possible or necessary
4) requiring immediate payment on any BIN or fixed price listing
5) deciding ahead of time which countries you will and will not ship to, and knowing VERY well exactly what it costs to ship an item of the packaged weight and size you will end up with
6) insuring and tracking/delivery confirmation on ANY item; unless you are willing to lose both the money and the item, this is absolutely positively necessary
7) communicate with your buyers! Send an end of auction email, send an invoice, send a thank you for payment with info about when and how you will ship, and send an email with tracking/delivery confirmation info once it has shipped.
8) leave feedback LAST
9) if all else fails and you just can't deal with all of this, consider using a trading assistant. It can be worth the percentage they take in order not to have to deal with the headaches.
There's more, but those are the most important things I can think of right now. Good luck!