“A journalist taking a source to a bar to get them drunk, or to have a clandestine meeting, is NOT a reputable business meeting. A meeting typically involves multiple people, which requires a table, and once you have a table (as opposed to bar stools), it’s a restaurant, meaning your question becomes, how to act in a treiff (non-kosher) restaurant.”
I didn’t say it was to get them drunk or to have a clandestine meeting. Let’s say I am writing an article about Sudoku and other puzzles, and I want to interview some people who are geniuses and do these difficult puzzles all the time. The trouble is that these people are somewhat reticent, and they don’t have much to say to me. So am I going to invite them to come into my office to talk? No, I won’t get anything out of them that way. I’ll probably suggest that we meet somewhere public, somewhere casual. Perhaps a bar. And I’ll probably want to meet with them individually so that they don’t intimidate each other. Perfectly reputable, perfectly businesslike (remember, I am getting paid for this article). I’m not trying to hide what I’m doing or to get the guy to drink so he’ll talk; I just want him to feel comfortable, and this atmosphere itself makes him comfortable even before he has a drink at all.
Incidentally, a “meeting” can consist of two people, and three or more people can congregate in a bar sitting on bar stools and have a meeting.