Not to be confused with frosty windows, two different things.
Presumably you have a frosted window in your bathroom, it would be insane not to. How effective is it in stopping observers outside seeing your naked form? I've noticed that there is varying degrees of frostiness (proper name) and some don't go that good a job of letting you get an eyefull. I noticed this when having a cigarette in my garden and looking at the houses oppposite, there was nothing sinister involved. Could see a man wearing an AVCO West Ham shirt brushing his teeth.
Also anyone seen curtains in a bathroom, doesn't seem to be a thing really.