Just saying SNS is, on one level, something of a solution in search of a problem. That is, WRT significant damage outweighing the benefits of continuous gas exchange. OTOH if the problem is how to get a starter oxygenated, of course it's a great, "cheap 'n' easy" solution. Not as effective as pure O2 up front, which in turn is not as effective as continuous stirring or shaking, but surely provides as much oxygen as air can provide at the most critical time. On that front, addressing Steve's original question, I really like the paint stirrer idea as an easy, and safe, way of aerating a starter in a carboy. I wouldn't want to shake one like it owed me money.
Back when, before I had an O2 stone or a stir plate, I used to do starters in a jug and shake them until foamy. Then I'd give it a minute or so of swirling and agitation every hour for the first few hours. That would get some CO2 out and more O2 in, providing some of the benefit of continuous motion on a stir plate or shaker table. Do you ever add that to your SNS routine, Denny? Or is it just start it up and let it go?