Instances can reboot, under operator control or due to a crash, and still retain their existing hard drive storage. Only less frequent 'instance termination' causes a loss of hard drive contents.

True, there are no guarantees that any instance won't be terminated by Amazon or other system failures at any time, so you're supposed to have your own backup and persistence strategy. But in practice, full terminations are rare, and Amazon has even given warnings when system upgrades mean large instance turnover is expected. (Though, there is no guarantee they will do so.)

So the falsehoods above are "[data is lost] if your virtual server goes down for any reason" and both concrete examples given, "taking it down to install security patches" and "system crash".