With a blade you'll have to press down to a reasonable degree in order to get the water off, or it won't do anything.
With a waffle-weave towel you can either "dab" at it (as Rob described) or you can lay the towel flat over the surface and pull it gently towards you. With either of those I think there will be less force pressing any grit etc into the paint compared to using a blade. Yes, if you pressed hard with a rag it could do damage too.
Fair enough, although with a decent finish, I needed virtually no pressure, other than the weight of the blade itself, to drag the very beeded (sp?) water off the surface. Plus of course, a wipe of the blade every pass kept it squeeky clean. It was imperative you only ran the blade over a wet surface though, otherwise it grabs on and that is not particularly good.