Disable self-signed certificate warnings when visiting .onion sites

I suspect it's fairly common (or at least, we hope it's common) for users to type https:// instead of http://.

If an onion site doesn't support HTTPS, the user gets an error page because it can't connect. If it does, the user gets an invalid certificate or mismatched certificate warning. CAs do not (yet?) issue certificates for .onion domains, so there are no valid certificates.

But the security of the .onion URL ensures we're talking to the valid so, so ignoring SSL mis-configurations should be safe, as we already have authenticity, integrity, and confidentiality. Right? Or am I missing something?