Well I have a few problems with the "scientists" quoted and their concerns.
The "scientist" quoted in New Scientist is one Mr. Neil Davison, from Bradford University in the United Kingdom. More specifically Mr. Neil Davison is the "project co-ordinator" for the "Bradford Non-Lethal Weapons Research Project " (BNLWRP) . The BNLWRP is under the "Department of Peace Studies", which was initially started by the "Society of Friends" (which I assume to mean the Quakers). The BNLWRP lists that one of its research objectives is to "Highlight the ethical questions that surround the research, development, deployment and use of such weapons. " Furthermore, the biographical information for Dr. Nick Lewer, head of the BNLWRP states that the grant under which the BNLWRP operates allows for research on the "concerns" that NLW systems present "...particularly within the context of the dangerous implications for the suppression of civil dissent and civil liberty. " The grant is from the "Joseph Rowntree Charitable Trust", and who is the Joseph Rowntree Charitable Trust? Essentially they are a large Quaker group in England. There policies include "control or elimination of specific forms of warfare and the arms trade" and "pacifism and conscientious objection to military service ". That's a lot of Quaker influence.
Now, I have absolutely no problem with peace or peacemaking (unless of course it is from the "Liberaliti" brand of "peacemaking" which as I have described before is really just a cover for communism/anarchism and the abolishment of the United States). However I do have a problem with groups influencing the development and research of systems designed to protect the lives of U.S. military forces or law enforcement, who are at their very nature opposed to the concept of a military at all and those influences being presented as "science".
That said, let's take a little look at the "Active Denial System" and the possible "damage" that it can cause.
"...Neil Davison, co-ordinator of the non-lethal weapons research project at the University of Bradford in the UK, says controlling the amount of radiation received may not be that simple."First off, it's not a "radiation" weapon in the common vernacular use of the word "radiation", it is a microwave weapon. While technically this is a form of radiation, it is not ionizing radation, which is the main type of radiation that is the big bad boogieman in our society. Secondly, "controlling" the exposure to the beam is relatively simple. The beam heats the top 1/64th of an inch of the skin, creating a burning sensation akin to "...touching a hot frying pan or the intense radiant heat from a fire". A human beings natural reaction to such stimuli is to jerk away from it (that crazy momma nature, giving an instinct towards self-preservation!).
"What happens if someone in a crowd is unable for whatever reason to move away from the beam?"
Seeing as how "...a 2-second burst from the system can heat the skin to a temperature of 130° F" and it is apparently designed to sweep across a crowd, the odds are that the crowd won't be around for very long. Also "Someone would have to stay in the beam for 250 seconds before it burnt the skin". For the mathematically challenged, that's over four minutes. If there is a crowd or individual, that can stand their ground against a burning sensation akin to touching a hot frying pan for over four minutes, then I would be more concerned about the soldiers using the ADS system and their security.
My final arguement in favor of non-lethal weapons systems is very easy: A burn on the skin is a lot better than dying from lead-poisoning from taking a couple of rounds from a rifle or pistol. To argue against non-lethal (or "less-lethal") weapons systems is asinine.
Unfortunately we live in a world where people want to kill us. Be that for ideological, religious, political or other reasons, they want to kill us. Not give us temporary burning sensations on the skin, not make our ears ring for a little while, not cause us to feel temporarily nauseous. They want to kill us. We are one of the few countries in the world that would even think about creating non / less lethal weapons to use in a war zone. But there are groups and people out there who don't believe in the concept of war or defense, or at least not for the west. Those who think that any response to violence is bad. To them I say this: go to Osama bin Laden al-Qaida et al and start preaching that to them. The West is already getting soft about our responses to terrorism and violence, we are getting so bad that non / less lethal weapons are areas of "concern" to us. Preach non-violence to the actual violent groups, not to those that are defending themselves.