Would be nice for forums that don't use it. How is there not an option?

Member Groups > Manage Member Groups > GROUP > Global > Remove Status Update ability

Still shows in profile?

Still shows in profile?

Not perfect... but close to what you ask, and a lot closer than the suggested setting.

Could also delete the tab config file, but that's beyond a mod to accomplish.

Hello.

You can add the following line to your conf_global.php file.

$INFO['su_enabled']					 =	   '0';

Good enough, thanks.

There's also some details I posted here to remove them (note: unsupported file edits) from the notification area.