At least most any shift they'd likely come across will NOT have straight cut gears!
(I'm sure a lot of us old coots learned how to shift gears with OUT using the clutch; right?)
VW vans had that long clutch cable, very prone to break. I carried a spare, of course, but I used to drive around for days (sometimes a week or more) without the clutch, until I felt like rolling around underneath to replace the cable.
I’ve taught a few people to drive clutchless as well. The problem is that for quite a few years now, everything has that safety switch so you can’t start the engine in gear. Still have to use the clutch from a dead stop (unless you bypass the switch), but then you’re OK. Parking so you can roll down a hill is another option.
And you’re right, synchro makes it a whole lot easier.