For future reference, the key here is that it's a polymerizing oil. Polymerization is exothermic, or else it wouldn't happen to begin with (second law of thermodynamics - speaking very roughly, a polymer is a lower-entropy configuration than a puddle of unchained molecules, so it has to be offset by an energy release such that overall entropy increases) so any time you encounter a polymerizing finish you should just assume that the rags have to be handled with care.
The reason varnishes generally aren't a problem is because the vast majority of the polymerization happens during manufacture, when the oils and resins are "cooked" together to create the varnish.
The article looks interesting, except that I really hate abusing my show surfaces like that. I'm a bit of a "planed surface purist".