It's in a long line of well-known security UX practices-- what better way to teach the user the right choice than by guiding them down all the other paths first?

Here, let me tab-complete my pubkey so we can continue this discussion in private:

   -----BEGIN OPENSSH PRIVATE KEY-----
   b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAAAMwAAAAtzc2gtZW
   QyNTUxOQAAACBGCHC9jhyIIOyoFx5PP9wpaRE/8jIksP+ET++fca82pQAAAKCSve3okr3t
   6AAAAAtzc2gtZWQyNTUxOQAAACBGCHC9jhyIIOyoFx5PP9wpaRE/8jIksP+ET++fca82pQ
   AAAEDbv7BsaZKNPQZSGeT8IBMb2z+lNCpTLZ7VXprw84XsZ0YIcL2OHIgg7KgXHk8/3Clp
   ET/yMiSw/4RP759xrzalAAAAFnlvdXJfZW1haWxAZXhhbXBsZS5jb20BAgMEBQYH
   -----END OPENSSH PRIVATE KEY-----