As a matter of fact, we did just that during the 1/3/04 Western a few weeks ago. Our son's 3 year birthday is thie coming Feb 14, so he was about 5 weeks shy when we cruised. Disney would not allow us to make a reservation for him through them since he wasn't 3. They said we would have to check with the Chankanab folks. So we had reservations throught Disney for 2 adults and my other 2 older kids, and we brought our almost 3 year old. He was allowed to ride on wife's lap free without an excursion ticket, which is a wrist strap they give you to wear (no seatbelts in our cab anyway). At Chankanab, they let us carry him onto the Dolphin pier without any kind of ticket (we did ask), so we ended up not having to even pay for him. One of us was just going to hold him on the observation pier, but they motioned for us to get in on the sunken pier with him, so he got to participate, and loved every minute of it! Of course they probably thought they'd have a better chance of us buying a video for $29 afterwards if he was in it!