Re: "Non Enemy Troops"
Who told you only Assad uses Barrel Bombs?
I cannot be arsed to look it up now, there was a cute photo-essay in the Graunidad showing opposition weapons workshop where they were welding propane gas bottles to the solid fuel rocket engine off a Grad missile. Cute. Stunningly cute. Average range under 1km. Precision - utterly useless for any military use. Now, lobbing it into the middle of the Sunday market, bonus points if the market is in a Shia, Allavite or Kurd village, that is an entirely different story. But you know, the celebrated freedom fighters do not do that. At least so we claim (unless a clueless journo catches them when they are doing it and does not know what picture did he take).
I am not going to elaborate on what exactly can you put in a gas bottle if you do not cut the head off (so you can fill it with solid explosives). If you leave as a "gas bottle" it opens a ... err... a whole universe of opportunities for terminating the neighbours.
By the way - there is f*** all way to distinguish between a barrel bomb and one of these. The effect is the same. If a plane is in the vicinity, the plane is blamed, though quite often it has nothing to do with that - it is just the opposition groups settling scores and blaming Assad (not that he does not do it - he nowdays has better weapons courtesy of his Russian and Iran friends).