Agree.
There are loads of non subs that are fine.
It's the new guys who join and spam every forum 10 threads deep
like that goofy guy did a a few months that get the established non-subs
a bad name.
A time lag between joining and posting may work.
Perhaps offer a reduced first year sub to non-subs that have been here
for two or more years that may induce some to join.