As a player or as a referee, I can do without torture happening in my games.
My line goes as far as “lets tie him to a chair, and wave a dagger around to intimidate them”. Anything more than that and it gets kind of icky for me. The immersion is broken and the situation snaps into clear focus: I’m sitting with a group of adults whilst one of them describes ordinarily unmentionable ways of compelling someone to hand over some information, and they push it and push it in the hopes of getting advantage on their roll.
I’m happy to say that this almost never happens. It’s happened a couple of times, and when it has most people have understood and found another route. On one time though, the DM said, “well, you need to find another way of getting him to tell you the information then.” It didn’t feel like there was another way – the bandit was steadfast and cared for nothing but the end of Chult. We didn’t get the information – I expect we weren’t supposed to capture the bandit, but a dice roll got out of the DM’s control.
On a few occaisions we’ve chosen “the scene fades to black as you begin your interogation” method. This is largely fine! (Your mileage may vary.) Nothing is described, other than the character’s intent, and then an intimidation roll is made. This is fine.
However, you still have to journey with adventurers who were willing to do that. (This awkwardness only extends to the character – I’ve never played with genuninely sadistic people, I assume.) In world, I’m not sure how that would sit well with everyone. Rarely are there consequences.
So, as a general houserule for games I run in the future, I have this:
There are other tools and you should start each campaign by checking in with your group for them. The “fade to black” option is similar to ‘lines and viels’ that is commonly used. It’s not just about super grim stuff like this: double check if your group are okay with fighting spiders, as you don’t want to be kickstarting anyone’s phobias.