Spick, it's not safe to let cats out everywhere - when you're in the middle of a large city e.g. (Cologne in my case)
I know of no visitor who complained about a "smell" - not even when I had very ill kittens at my office for 4 weeks because I couldn't take off (happened 3x so far) - but I could clean it there right away and always had a window open. Same goes for my bathroom.
And the fond way you describe your cats, I just can't believe, you'd chuck them out <img src="/ubbthreads/images/graemlins/winkwink.gif" alt="" />
Kiya