Climbing Cats

This summer I'm staying in a rather nice townhouse or row-house type of place with some roommates. Beorn is away learning his new trade so I'm staying with roommates. Our kitties have been staying inside, but there is a lovely courtyard type backyard. The problem? The princess likes to climb. The courtyard has a sort of trellis or pergola over it, made out of wood. The cat can climb straight up six feet and then get onto the top of the pergola. Then she wanders around on the top rails and sometimes disappears. My fear is that she will see something interesting in someone else's courtyard and jump down. This evening BOK followed her up to the top. Since he weighs twice as much I was somewhat concerned that he might not be able to get down or might hurt himself. Now I have a nice big scratch on my arm. He wasn't too confindent in my ability to safely hold him while standing on a step ladder. I had to forcibly drag him down. Damn cats!