People will do the darndest things when they think no one is watching. Just think Tom Cruise in that scene from Risky Business. Michael Lewis wrote a whole book about the crazy antics of people when ushered unsupervised into a dark room full of money (Boomerang).
Operating in the light of day however is a whole different thing as we found out with all of those cables exposed by Bradley Manning and Wikileaks. What a surprise it must have been for all of those people that thought they could do whatever they wanted and no one would find out. I think it is safe to say that no matter your politics, those cables cut deeply into the public opinion of the people sending them.
Under the cover of darkness, people convince themselves that they are right even while pursuing the most evil schemes. I think this contributes to the negative opinion of lawyers -- who are always trying to make things even darker with confidential deals. This is getting harder and harder to do in the age of the web and the resulting free flow of information. Just look at the hole AT&T is digging for itself on the whole unlimited bandwidth business.
I admit that evil is a strong word for anything having to do with AT&T's billing practices. Unnecessary too because there are so many examples of people behaving in truly evil ways. The governments of North Korea, China, Syria, Egypt, Pakistan, and just about all of the rest of the middle east, most of Africa, and Russia depend heavily on the cover of darkness when they do what they do to the people they oppress.
Whether or not you agree with the intentions of the Kony 2012 campaign, anyone shining a light on bad behavior is doing good work. (here is a post about Bono's reaction to Kony 2012).
When I was in middle school, my family hosted two young men that had escaped from Uganda. They lived with us for a while as they were getting back on their feet after having run for their lives from Idi Amin's police. Ironically, they escaped under the cover of darkness.