It seems, however, that in all the offered specimens, that there, at least, is an inherent ambiguity in the
be- prefix as in become, which connotes a change to be sure, but it can be either a loss or a gain. Bereft and bereave do, deed, indicate loss as in derpivation or saddened emotion, but with the same ambiguity, you could also say they are adding deprivation or grief to the condition of the party or parties involved. Behead/beheading is the only one, so far, that seems to indicate loss only. Unless the ambiguity creeps in, perhaps, with its coinage in the days of yore when rulers asked for and were presented the heads of those ordered executed...whereby, in presenting such, you are giving the victim's head to, or beheading, the ruler (this is purely conjecture). Now I guess I'll have to scour the be- section of the dictionary to see if I can come up with any more examples that seem to purely connote loss/subtraction.
