I think that there are a lot of sellers out there in cyber world who are over thinking this. (Selling wholesale).
I read on one forum that one Etsy shop turned down wholesale offer for her things because the person just joined Etsy that day. No other reason was given as they thought the store was not legit.
My feeling is-- that is someone wants say 10 of one item-- I will give them a deal. That is wholesale. Wholesale to me-- is a figure that I am willing to part with the item for--my lowest price. I only do it for a bulk listing of at least 10 of the same item. Sometimes that is only 50 cents less or could be half of what I have it listed for. Know in your head your base price- that you will still make a profit on. You decide how many items constitute wholesale pricing to YOU. Every shop will be different. Stop worrying about wholesale formulas
I did have a shop last year come to me and ask if I would do wholesale. I did look them up on a google search and found out they were a B/M shop also. However, they wanted 10 different items and only bought 6 of each item.. I gave them a deal. Why not? It is still a sale and look how many things I sold. I still made money, tho not as much as if I didn't give a deal- But more than if I had only sold 1 item and the rest sat there.
Whether that person keeps them for themselves or resells the item- it is not my concern. They have paid for the items- it is theirs to do with. I do not worry about how much they will resell the item for-- it is not my concern. They know their market. If they are willing to pay your 'wholesale' price--- let them and wish them well.
As long as they pay you with PayPal-- make sure they are a verified customer... then do it. And you know what- they might come back for more and bring friends.
Please stop over thinking this... it is not that hard. You are a seller, You make your own rules. Make the deals as you want to. Either they want your things or not... and it is okay.