I've heard of others having this problem with cats and Maggie scratching posts. I've also heard of dogs marking their territory on them. As my moniker suggests, I have Maggies and cats. I've had maggies and 4 cats over the past 30 years and no issues. I was concerned with 1 new cat I had adopted and got some nicely patterned sheets to put over my MGIII's when not in use. They were easy to remove whn I wanted to do some serious listening. I had considered having an upholsterer (sp?) make something a little nicer. Since the cat pays no attention to them without the sheets, I can't really attest to the effectiveness, but they loked nice!
As Steve mentioned, pet stores sell a green apple spray, and probably other sprays, that are used as cat repellents. I tried the green apple spray with one cat and it had no effect on his behavior. YMMV...
Regards,
Steve