I suspect the mysql_enable_utf8 is derived from pg_enable_utf8, which simply sets the UTF8 flag on everything that comes back from the database.

Yes, sorry, I got it backwards. I was thinking the enable_utf8 affected data sent to the DB, but it affects DB obtained from the DB.

Either way, it's a very incomplete system. Only UTF-8 is supported (right?), and it's broken when it comes to data sent to the DB.