[monstermunch]

Honestly I'm not 100% sure. Full A record failover is a paid feature which I don't pay for, but it seems like adding 2 A records does more than just round robin the DNS

If from a test machine I am loading the site via the VPS and I power it down, as soon as I refresh the page it ends up pointing home with zero downtime

[onlypositive]

I guess the proxy IP is the same. They must just run a single tunnel per hostname with multiple upstreams.

Nice find ;)