I know this is a little off topic from this thread, but it's still regarding taking flash photography on a dark ride. You probably don't want to do that! In addition to it be annoying to other guest, you'll completely lose the effect of the ride.
If you use a flash on a dark ride, you tend to wash out the photo. When I'm taking photos, I'm usually trying to capture the experience. By washing out the photo you lose the true perspective of the ride and how it actually looked when you rode the attraction to begin with!
In the darker rides, the displays that you are meant to look are lit (although sometimes dimly lit).
If you really want to capture photos during dark rides (and keep the "feel" of the ride), up your ISO on your camera (or better yet, use a lens that F-Stop of 1.8 or lower). Put your exposure on "spot" and your camera into burst mode and your flash OFF.
In the photo below, if I had used a flash, I would've completely lost the "feel" of the shot and lit up everything (including the car I was riding, complete with other guests). Possibly washing out the photo.
Disney World Vacation 2011 by
Snapaniac, on Flickr