Moksha has a module called "places" you can set to mount USB drives on insert. I don't have it checked in this screenshot, and it appears it's not enabled by default on BL6:
Thunar also has a similar setting under volume management, but that doesn't seem to be enabled either. So I'm not sure how BL6 is mounting USB drives actually...
Yes, I can confirm something is wrong. Eject in places module does not work correctly. I even saw wimc's autentification password request. I need to do some research.
I only briefly tested this solution. In my case the automount is gone but no password for unmount. Maybe some guys can offer a better solution than me...