BMW's actually have a low level sensor as well as a pressure sensor (at least my old E46 does). Therefore even in the event that you don't check the oil you should get a warning before you get the pressure drop.
Doesn't stop me from checking regularly, but does give a small comfort factor.
Gone: Fiesta - Focus - E46 320dSE - E91 330dMSport - E82 135iMSport - R55 JCW Clubman
Now: M135i with lots of toys