Well there we are then - no sites i've been to allow people to throw BFG's over shoulder height or drop them on people from above - this bloke broke the rules and someone got hurt - not surprising as airsoft is an adventure sport. Two lessons to take from that: 1) the rules really do have good reasons behind them, and 2) stupidity is an ever present danger so you had best take your own personal protection seriously.
If someone had fired a gun in the safe zone and taken someone's eye out, what would we be saying? That's against the rules too. Personally I get pretty irate with anyone who points a gun at me in the safe zone, let alone dry firing, regardless of the rules, whether that site's safety briefing has said no shouldering as well as no dry firing, and whether they have no mag in, etc and I'm pretty unhappy when sites do not have marshals check that players returning to the safe zone have de-mag'd and cleared their chambers, because then i feel unsafe removing my eyepro at all.
I would expect sites which allow TAGs to say that players should not aim them at people, in the same way that they often say that pyros should not be thrown at people, but I'd feel a lot safer being hit by a TAG than a BFG. We all know however that when we throw a pyro into a room, for eg, we do not know for sure that it will not hit someone, so conversely when we are defending in cover which obscures our exact position, it's possible that a thrown pyro will hit us without the thrower being in any way malicious or dickheadscious. I don't usually wear a helmet, but I accept that I should and if I do ever get sparked out by some penis behaving irresponsibly, I will not blame the site, or the sport...