On Sat, 04 December 1999, "Alex P. Rudnev" wrote:

It should be your problem. You simply loss the part of connectivity...

The real world is more complex than you drawn below. There is many reasons causing people to announce class-B networks with the short prefixes.

Can you give a concrete example? In most of the cases I've seen the people wanting to break up an class-B network either because 1) they don't want to return the class-b network to ARIN and get two or more appropriately sized blocks, or 2) their upstream provider won't aggregate announcements from multiple connections, 3) they made a mistake and announced their IGRP subnets via BGP.