We are going to CSS (2nd time) November 2011.
This time we plan to do different tours (ocean horseback and dolphin encounter).
Last time we did zip line and Dunn's River and made sure we weren't there when the cruise lines were in dock.
Do we need the same precaution for these other tours?
I don't know about the zip line, but we did the dolphin encounter, and I don't think it would be too affected by cruise ships. The group sizes are limited, so as long as you have a slot, I'd say you're fine. Also, while it was a great excursion, it's on the pricey side, and it's not really considered the "must-do" thing in Ocho Rios, so I wouldn't think you'd get too many cruisers.