I'm inclined to call bullshit on the video. The drop used is minute, in the other of several, maybe tens of milligrams. This might be enough to just nudge a watermelon of a pole, but not enough to 'completely obliterate' one using any chemical explosive.
Chemical explosives hold a limited amount of energy per mass. In fact, there is less energy in a kilogram of dynamite or TNT then there is in a kilogram of gasoline. The only difference is how quickly that energy can be released.
In the broader sense: it would be perfectly possible to reproduce that result with a pen-sized explosive device. A pen could hold 10 ml or so of nitroglycerine, and a blast cap to set it off too. While that would not be a 'huge bomb' by any standards, it could be enough to blast out an airplane window causing a serious incident.
Should we be worried about that? No.
We should accept that it is possible to cause a large number of victims using very small devices of various natures in some circumstances. Measures like limiting the amount of liquids someone can take on a plane are completely useless in this regard.
Even a 100 ml bomb could blow a hole in an airplane hull or window, and if someone would set that off in the front rows of seats, chances are that matter blasted out would end up in the engine(s) on that side, resulting in a plane with limited areodynamics, rapid decompression, possible damage to flight controls, and loss of one engine. A plane could be safed despite all of that, but its by no means guaranteed and it'd be a very serious incident almost guaranteed to end up in at least injuries.
Somehow people obsess about tiny bombs on airplanes, while all other forms of transportation bascially allow you to put a 20 kg bomb in the luggage, and not even travel yourself (getting off the train or bus before departure).
Terrorists prefer to target airplanes because this instills a fear to travel more than anything else. If the goal is to actually kill large numbers of people, they resort to much easier targets - we have seen this on european subways, as an almost daily practise on isreali busses, and even bombings on nightclubs on bali where a van full of explosives was simply parked out front and set off.
Increased air security -only- is a nuisance to passengers. Terrorist that set out on creating casualties dont have to resort to high tech small explosives. We obsess about a liter bottle on an airplane, while it would be trivial to drive a truck loaded with several tons of explosives into a sports arena, potentially killing thousands in one shot.
