Re: Sky Ride Safety?
On http://www.rideaccidents.com/rides.html they report some of those early gondola accidents that killed people.
Looks like one in 1978 at MM and one inSix Flags Mid-America that same year.
1979 One at the Texas fair - interesting it says "The U.S. Consumer Product Safety Commission concluded that the ride's operators knew of defects in the ride, but failed to report them. The woman won a $3.1 million settlement on the basis that the ride had been operated negligently in high winds."
So I guess a defect of some of these rides is that they cannot operate in high winds. Which I believe was/is because the way these rides attached to the cables require gravity to apply the grip needed to stay attached. In high winds or bouncing of the cable would reduce the "grip" and allow the gondola's to detach mid-ride.
Even Google'ing for other gondola/skyride/ski-lift ride cable breaks - I only found this one that looked like it was caused because the cable snapped. http://www.foxnews.com/story/0,2933,503024,00.html
Looks more likely that your gondola will drop off the line due to wind, the cable fall off the towers supports due to wind, or the support tower fail due to ice - then the actual cable snapping.
Ice-jacking: http://edition.cnn.com/2008/WORLD/americas/12/18/gondola/index.html
Clamp Failure: http://community.seattletimes.nwsource.com/archive/?date=19951225&slug=2159463 That didn't sound like fun - "Witnesses said the accident caused some skiers to jump for their lives,while others waited suspended up to four hours in the dark on swayingchairs. About 200 of them were rescued by ski-patrol members using anemergency rope system."
As for testing the rope - I read they can use Electromagnetic induction to test for those hidden dangers that they cannot see.