Bava Batra 47: Thieves and Their Rights to Ownership

More on the craftspeople and the sharecroppers -- where they don't have the rights to the presumption of ownership, but their sons would. Whereas if the father's "profession" is robbery, the right to the presumption of ownership only kicks in for the grandson, not the son. Why the distinction? Also, all of the categories of people who can't establish a chazakah can still bring other means of proof to claim (and acquire) property -- except for a robber or thief. Plus, when even a robber or a thief has recourse...