I do it, but it mostly only happens on punts when there's rest between rounds and I'm more likely to catch a chill just lying there cuddling without a cover.
However I don't see more than a few punters a week, and have the attitude of washing all my sheets after a punt (I can't stand a mismatched bedspread).
Those who are doing multiple in a day, I can certainly see their reason for it, easier to wash one sheet from each than several sheets from each.