When you get a bug in your knickers to use the spot/steam cleaner to clean the arms and cushions of the couch, you will be horrified to see the brown, no-longer-see-through water coming off of the upholstery.
You will then turn around dump all of the dirty water onto the carpet.
Haha! The reservoir doesn't seal!
p.s. I wish I could warn you further in advance, really, but it's just too funny.