That is my problem. Well, it's not MY problem. One of my cats has started spraying. He doesn't do it all the time. Seems to be when he's anxious or over-excited. I love this cat dearly. We've been working on this issue, and every time I think we've got it licked - I catch him peeing all over the shower curtain.
I have to be more diligent with the Feliway. Which seems to work for the most part. Though sometimes, it almost seems to excite him more. In the end, I need to pay more attention to his triggers. And avoid them.