As I mentioned in one of the other paladin topics going, my yardstick of what LG characters can do is what the cops on Law & Order can do. By way of example, in one interrogation scene on that show, it was pointed out that the police could use deception to get someone to confess, as long as the deception wasn't one that would cause an innocent person to confess.
I also read a book just recently called The Interrogators, about US Army Intelligence in Afghanistan. They had very strict rules on how prisoners were treated; for example they couldn't use Sleep Dep, if the interrogator got a break to get a meal and take a nap, the prisoner had to have one too. It reminded me a lot of the anti-hazing rules of Boot Camp and the occasional fraternity (not that I've ever been in a frat).
I haven't watched much of the Closer, but apparently that's Kyra Sedgewick's thing on that show, you put her in a room and she gets the confession. (I did catch a recent episode where the DA was reluctant to criminally charge two doctors, and Kyra kept going in there getting the doctors to admit to more and more until in frustration, she demanded of the DA, "Just tell me what you need them to say to prosecute, and I will go in there and get them to say it.") Also, on The Shield, Dutch and Wyms run some really good interrogations that are pretty much by the (tv) book. Even Mackey stays pretty legal in the interrogation rooms, because they're cameras in there. When he catches people out on the street, not so much (but then, Mackey's not LG by any stretch).