I have a cat who, since we got her (12+ years ago) refuses to use the litter box for #2. She does, however, limit such activities to the area AROUND the box. We've dealt with it by putting down plastic and cleaning up after her. Recently SOMEONE (of our three) took to peeing on clothes left on the floor. We responded by washing the items - and throwing away things that were just too far gone. We don't have a couch - just 2 recliners and 2 beds. None of those appear to have been peed on, just clothing items left on the floor. No way to tell which of the 3 it was, and too expensive to take them all in to test for UTIs - no other signs like blood in the litter box, etc. I think it was a protest against a recent litter change to pine pellets, because when I switched back to one-pine and one-clay box, the peeing seems to have stopped.
As a cat owner I realize that sometimes things just happen. In the case of the couch, I would have put a plastic cover over that, then a cotton/easily washable over that so it could be presentable for guests and quickly washable in case the cat peed or coughed up a hairball or whatever. When we HAD a couch, we had a cover on it, not due to pee, but because of the random hairball or shed fur; it was easy to strip and wash then put it back on. I would have warned a guest that the couch in question was a bit questionable due to cat behavior (I wouldn't have said WHAT behavior) and after I assured them the couch had been cleaned, offer alternate seating instead.
And yes, I have been told to put down the cat in paragraph one. I ignored that comment. When the person kept repeating it, I replied, "I realize that's your opinion, but I'm not going to do that. Please don't say it again." The person did get huffy, but they didn't repeat it. I was fully prepared to walk away if they did though.