Hey there, sometimes-wheelchair-user here. Afaik the law is also the same where I live, the spot has to have a sign. Here, when there's a spot with just faded paint, it usually just means that the handicap spot got moved somewhere else. The only thing I'd suggest is if you don't already, just check and make sure that there is a spot somewhere else that does have a sign. If there isn't, it's probably because the owner just didn't mark the spot properly. In that case, it's best to leave it open for those who need it, even though it wouldn't technically be against the law to park there.

I'm not accusing you of anything, just putting this out there in case the situation comes up. Cheers!