It would be overstating things to say that things were always very civilised in Slat's in my time, but there was never any pint-throwing.
Mind you there was a confrontation in connection with the domestic affairs of one of the sons (my lips are sealed), but it didn't degenerate into violence inside the pub. But it was the sort of episode which would be used to justify the JB Keane attitude, as if the same kind of thing didn't happen among other groups in society.
Around the same era, the girl who subsequently became my wife was the cause of a Hollywood-style Irish bar brawl between apparently "respectable" people in the very respectable Baggott Street (not O'Donoghues's, one of the places with higher social aspirations across the street from Doheny and Nesbit's, home of the Dublin branch of the Chicago school of economics). Fortunately I wasn't there and didn't even know her at the time, so I didn't have to get a bloody nose to prove my undying devotion.
One of the things which struck me most about John senior was his acute sense of respectability - he reminded me very much of my own mother's upper-working/lower-middle-class Edwardian social values, even though she didn't think much of my hanging around with travellers. I unintentionally offended him once with what was meant to be a complimentary remark about Davy Spillane's adoption of the travelling style of piping. I wasn't even aware I had given offence at the time, but Johnnie junior came up to me a week later in Slat's and I wondered if I was going to get a dig without knowing why. But he simply conveyed in very elliptical terms the fact that I had given offence, and when I met John I made a suitably elliptical apology which he accepted in equally elliptical terms. A decent man, and Mary was also a decent woman.