[908B64B197]

I don't think people understand what "public" on the internet means.

If the specific people can get to it without auth, so does everyone else.

[ghusbands]

There are a large number of services (Dropbox, Youtube, Google Docs, Office 365, etc) that use unguessable URLs for sharing and hence clearly don't share your idea of what it means to be "public" on the internet.

[dredmorbius]

"Unguessable" presumes "not leaked in the course of typical access", which seems to be an increasingly invalid assumption.