Not an example a lot of people here are familiar with, likely, but J.D. Robb's "____ in Death" series has a cop whom I consider LG (although shading toward NG because she lets her computer-hacker husband give her information that she knows he gets through illegal hacking). She does some great interrogations.
In a D&D world, a LG fighter with ranks in Intimidate would, in my book, be more likely to talk implicitly than explicitly about consequences. The "you're going to get ____ in prison" thing doesn't work for me as Lawful Good, personally -- I consider that chaotic behavior. (For the record, I consider implicit "I'm going to allow ____ to happen to your wife/sister/children" to be evil.)
Examples of things I'd be perfectly fine with:
"You don't want to talk to me? You don't want to TALK to me? Somebody's summoning demons to KILL people, and you know something that can make that stop. Let me make this clear to you. When I find out where the summoner is, I'm going to go there, and I'm going to kill them. If they summon the demon, I'll kill the demon. If they've got guards, I'll kill the guards. Innocent people are being killed in ways that would make you sick. I will kill ANYONE between me and my goal. Where do you think you're standing right now?"
"Your boss told you not to let anyone through that door, huh? I get that. I respect that. Two things to think about, though. First, how are things working out for your boss these days? You've seen the bodies, you've heard the rumors. You want to be be around when he loses it entirely, when he's killing everyone he can see? And second... I'm confident enough to take on your boss, man-to-man. Unless you can say the same, you're out of your weight class. Now, either get out of my way or give me your best shot."
"Why should you work with me? I'm trying to save this city from something that would kill every living person inside these walls. That includes sewer scum like you. If you help me, I'll forget about the scar on your left hand or the faint accent you're trying to hide, and if the time comes when I come to take you down, you have my word that I'll give you a fair chance to surrender. And if you DON'T help me? I'll take you down. Not your organization -- there will always be a guild. I mean YOU. Personally. Destroying your little empire will be my pleasant diversion when I'm not dealing with REAL problems. Are we clear?"
"I need to know where the wizard is, and I need to know NOW. I can't take prisoners, and I can't wait for the guard to take you in. For that, I apologize. Tell me where the wizard is, and I let you run. Lie to me or keep that stoic silence, and though the deed may haunt me for the rest of my life, I will execute you now. I have neither the time nor the inclination for torture."