Has a vehicle ever fallen off an Ezy Lift System where its the fault of the designer? This has happened in quite a few cases to the chain lifting system.

No way. And there never will be a risk with the Ezy Lift
system because of our engineering technique. In my opinion
as an inventor and engineering designer, the chain system
is the unsafest system around - there have been many failures
such as chains breaking and stretching, the expense of having
to replace chains every few years, plus examples of the chain
curling over the sprockets making it a very difficult task of
unwinding the chain and correcting the problem.

In short the Ezy Lift system is by far the superior system for
installation, maintenance, reliability and safety.

This Q&A was found on Ezylift : http://ezylift.com.au/modules/smartfaq/faq.php?faqid=4