It seems to me like there's room for improving your customers' awareness around what is required for HA and how to tell when they are affected by a hardware issue. On the other hand, it may just be that the confusion is mostly amongst the casual onlookers, in which case you have my sympathies!
I'm not sure on this, will it make any sense - customers who DON'T WANT to be aware of what is required for HA (say lonely devs) choosing such a hosting types. Even if you put educational articles, I'm unsure it will be used. Putting some BANNER IN RED LETTERS into CLI output + link to article may work, though.
$ fly volumes create mydata
Warning! Individual volumes are pinned to individual hosts.
You should create two or more volumes per application.
You will have downtime if you only create one.
Learn more at https://fly.io/docs/reference/volumes/
? Do you still want to use the volumes feature? (y/N)
(and yes, the warning is already even in red letters too)
I agree, articles tend not to get read by those who need them most. A warning from the CLI and a banner on the app management page with a link to a detailed explanation would seem like a good approach.
edit: sibling post shows there is such a message on the CLI. The only other thing I can think of is an "Are you sure you want to do this?" prompt, but in the end you can't reach everybody.