I've seen them all over public places in Colorado, including airports (Durango for sure, and I think Denver, too) and ski resorts. I'm guessing it's something a

I've seen them all over public places in Colorado, including airports (Durango for sure, and I think Denver, too) and ski resorts. I'm guessing it's something about building/plumbing codes there. I've never seen (or smelled) and problem with them.