If you can do validation from a perspective where your ISP can send you a full BGP table, you should be able to keep track of how recently the most specific route to that destination has changed; something that has changed recently or that currently has an AS path different than what has historically been typical may be suspect.
AWS does have some network diversity in different regions; they apparently do not operate their own backbone to interconnect the different AWS regions.
(And for all that Hurricane Electric seems to have not been doing a great job of filtering BGP announcements from peers, they do seem to have pretty aggressive pricing on colo space in their Fremont data center where they can provide a full BGP feed.)
AWS does have some network diversity in different regions; they apparently do not operate their own backbone to interconnect the different AWS regions.
(And for all that Hurricane Electric seems to have not been doing a great job of filtering BGP announcements from peers, they do seem to have pretty aggressive pricing on colo space in their Fremont data center where they can provide a full BGP feed.)