Cannot break Minecarts or Boats while riding them

Prior to 1.6, one could break a minecart or boat while inside it as a simple, easy, functional way of collecting the minecart and exiting the track. Without this functionality (presumably a bug with how ridable entities are now handled) "dismounting" moving minecarts and boats allows for very little, if any, time or ability to reclaim your moving vehicle before it speeds away on the track.