And when do you think the blankets, bedspreads, or comforters were laundered last??? They weren't!!!
Take a UV light to any of those rooms to reveal many of the different stains on those covers that rest so snuggly against your face.
http://www.testsymptomsathome.com/fot01.aspBetter check the sheets too:
http://www.metacafe.com/watch/939721/exposed_dirty_hotel_bed_sheets/