[jdamato]

We don't really know what EC2 does or precisely the type of hardware your VM will be spun up on. I've erred on the side of being cautious due to the vast amount of work being invested in timekeeping in various hypervisors. If EC2 knows that the TSC clocksource is safe on all of its hardware, perhaps modifying the Amazon Linux AMI to set TSC as the default clocksource would reassure many folks, myself included.

Advanced users that can run their own analysis or who have applications which would withstand potential time warps, are of course, free to ignore my warning at their own risk ;)