Instances can enable or disable the email verification and other measures, like asking why you want to join that instance.
I don't recall reddit being so liberal. I haven't used an account I didn't verified in the same day, so I can't say if it works, but I suspect they can enable different protocols for inspecting unverified accs.
As a side-note to that discussion: my VPN works with most services i can't access otherwise while reddit blocked me as I tried to access it to see for myself. I'm surprised.