well, more importantly, the difference between disabling and cleaning is that disabling is 'forever' (until switched back on) and not retroactive. Personally, I do *like* having thumbnails for the files in folders I'm working with, and I like that it doesn't have to re-generate those each time I visit the folder. However, once I'm done working with such a folder, that Thumbs.db file serves no further purpose and can be deleted.
Basically, it should be perfectly possible, technologically, to find all Thumbs.db files -over- a certain age (i.e. hasn't been modified in N days), and delete only those. It's what I currently do manually with Total Commander, but if this were integrated in an already excellent tool - hey, I'm all for it.