They are not rotating capacity for updates. They are patching a Xen security issue that will be announced on Oct 1. That is why they are rebooting machines and not forcing moves off of those machines. Otherwise, I agree with the advice.
I don't see anything about this on google.
I heard it is because they are having power issues within their datacenter.
XSA-108 2014-10-01 12:00 (Prereleased, but embargoed)
Anyone with anything concrete?
I still heard it is power issues.
stop/start can possibly put you on another physical - but it all depends on how aws has setup the hypervisors and their instance schedulers.
this, the maint from aws, appears to be security related - but that doesn't mean that aws is not getting folks off of old hardware if they have that desire.
It's more like a system restart with a little downtime managed by them.
You can try a stop-start yourself, but it's not guaranteed to help. And a restart yourself doesn't do anything.