It's designed to be capable of focusing up to a kilometer away, so short answer? Yes. Sweeping across a crowd would maybe cause a little bit of pain, but relative to the 5 seconds some can endure, thats nothing.
Well, that's something only time will answer. Since the people being hit will be a Km away and won't even know where the source of the pain is coming from, that actually increases the potential for abuse. You won't even have to be told
why you're being hit with it.
And you are right that the potential for abuse is in everything, that's why we need to be so careful about it. This isn't like some kind of Nuclear reactor that is designed for benefit but can be abused, it is designed for a specific purpose, to cause pain and subdue people. Some people may be able to endure less than five seconds, but since they'd have to travel several hundred metres at least to reach the source of the beam, that really doesn't matter. Personally, I wouldn't be surprised if there are several 'settings' the beam can go through, indeed, looking at the emitter on that jeep, there appear to be three emitter holes, small medium and large. Without details I couldn't say whether than is narrow, medium and wide focus, but as long as that potential for abuse exists, then we have to be wary.
God alone knows that Mace, Tasers and other forms of suppression have been abused in the past, this thing is, as you say, no more immune to it.
Jefferson's 'Eternal Vigilance' wasn't just a question of looking out from within...