Is connecting LEGO studs on Technic pins legal? I see it in MOCs all the time, and I’ve seen studs connect on half pins in official sets, but what about full pins?
The presentation that senior Lego designer Jamie Berard held at Brickcon 2006 and that spawned the entire legal vs illegal discussion can be found here:

https://www.hellobricks.com/pdf/jamieberard-brickstress-bf06.pdf

The particular case you ask for is discussed in slides 9 and 10: