Why not use LOTW for authentication?
It's been done before and if you are LOTW verified it means that you are a radio
amateur
It has also been done before (ab)using Echolink for authentication.
However they do not seem to like that, and probably rightly so.
(it puts the burden of license validation on them)
The same is probably true for LOTW when it would be heavily used outside its scope.
Some services require some form of client certificate, others (like NNTP) are better
off with a username/password. Both have to be catered for.
A good project on AMPRNet would be to setup a user authentication system that can be
used for our services without running the risk that some (ab)used party suddenly
draws back the support, or delays validation of new applicants (if only due to lack
of volunteers to do the validation).
Rob