Multiple routine momentary stops on HM, but never "stuck." I can't recall getting stuck on a ride at WDW.
At DL in California, we were stuck at the top of the big hill at Splash Mountain right before it goes down the drop. It took about 15 minutes for CMs to evacuate us. I asked if they could just push the log over the top, but they wouldn't go for it. We had to walk down the incline and thru some back stairs and hallways. CMs gave us an anytime any ride FP, but since we used a FP to get on the ride, I requested and we received another.
Back in the mid to late 90s, there was something called the Rocket Rods. It used the former People Mover's elevated track. It was notoriously unreliable and quite frankly a sucky ride. Anyway, we got stuck about 3/4 of the way thru the ride, and it took over an hour for us to be evacuated by a cherry picker truck. A CM handed us a slip of paper and told us to go to Guest Relations for some compensation. We expected maybe a free Mickey Bar, or perhaps even a comped meal, but lo and behold they gave us a free ticket to return another day.
Not Disney, and not me personally (so why are you posting this, nilla?), but we saw the Superman coaster at Six Flags Great Adventure get stuck going up the first hill.
For those of you not familiar with that ride, it's a suspended coaster where you are leaned forward to simulate flying like Superman, meaning riders were stuck on their bellies, looking straight down, held in by nothing but the harnesses.
I LOVE rides, and don't really mind heights when I'm on rides, but that would probably freak me out!
I feel like I'm "stuck" every time I ride Superman-Ultimate Flight at Great Adventure. They usually run two trains, and it takes so long to load, that your ride is already over and you're hanging there looking face down for a minute or two on the brake run before it returns to the loading station.
I prefer the loading style of Batwing at Six Flags America outside Washington DC for flying coasters. You're pulled up the hill backwards laying on your back, then the train flips over and you're face down frontwards for the rest of the ride.
Did you happen to notice if those riders on the incline were evacuated, or did they eventually re-start the ride and let them finish?