Our daughter just turned three. She is doing really good with pottying, and has been in panties for months. At first she had a lot of accidents, but it has been a LONG time since she has had an accident. Anyway, we are DEFINITELY doing pull-ups on this trip. We use them at night anyway, because she is very sporadic. 3 nights a week dry, the other 4 SOPPING wet.
But the real reason we will use them at the parks is because we have learned different things set her off. We went on a trip to Colorado about three months ago. She reverted to accidents BIG TIME. The reason? She had to go while she was on the plane (we had her in pull-ups just in case). She got back there and took one look at the big metal bowl and refused to sit on a toilet anywhere but in the hotel room the remainder of the trip. The toilet in the airplane freaked her out. She has to check out the toilets pretty carefully now, wherever we are. Since then, she has been pretty ok, but I have had a strange toilet at a restaurant set her off. And she refuses to go on a handicapped toilet. She has to have what she calls the little toilet. So based on that, when we are going to the parks for rides - pull ups it is, although she understands that we still try to keep them dry.