After reading and skipping over your post earlier, I saw that there are lots of views but no replies so I'll post my thoughts. Take them or leave them.
1. A poll is (IMO) inappropriate. After 20+/- years of ebay and a proliferation of other online sites, there are scammers everywhere. Especially for an inexpensive item in a specific size and style, it's not a high scam item this seller has and not usually prone to fraud.
2. As a buyer, you have a responsibility to vet your sellers by looking at their history, feedback, listings, descriptions, pictures, willingness to respond to questions, etc.
3. Personally, I don't buy bras, shoes, jeans, etc. online because every manufacturer, every style, and every body is different and I have to try on items for fit and comfort. If I owned a particular item and knew how it fit, I'd be willing to purchase another of the identical item if I needed another.
4. Regarding the bra and the seller, I don't see anything that indicates a scammer. While 100% feedback doesn't necessarily equate to a great seller, for the type of items she sells (and clothing is VERY difficult to sell and have satisfied buyers), it's wonderful.
5. Additionally, she has a 30-day return policy so if you buy and want to return for ANY reason, you can do so.
Scammers usually have high fraud and high demand items - expensive designer items, electronics, automobiles, etc. Bras, underwear and inexpensive clothes aren't what they're going to sell.