Well I don't know if anyone buys a domain, people and wanted to sell that particular domain to anyone, it can be a success, well I have faced problems while selling my old domains too. So in my opinion, Its a bit risky!
Yeah, I have done it and had great success with it, I don't do it now because I've found and thought of other ways of making money online
is your buyer only came from forum, ebay, and flippa? or, you have some great number list of buyers email?