A lot of that is because the collective on the Bell has a friction lock but no force trim- a year or two ago, a couple of IPs spread the skids by letting go of the collective in a hover with the friction dialed all the way off (friction was off because that's part of the control/hydraulics check procedure these days).
Still no excuse, but it helps explain why everybody is so gun shy coming out of the pipeline.
I wasn't a huge "YOU MUST KEEP YOUR HANDS ON THE CONTROLS" guy in the 60 and thought it was stupid when I had an XO who threatened to bench indefinitely people he caught doing it (despite the Skipper being a routine offender), but in the the 57, you really need to. And, I'm not just talking collective, the first student I ever let use the tablet, he took his hands off collective and cyclic immediately after start (waiting for the 1 minute idle time) to adjust his iPad - which is also when the PC is IN THE ROTOR ARC (!), then again both hands off during flight twice. To me, that's egregious, especially in the 57, and also inexcusable in the 60. Is it less of a risk in the 60? Sure. But it's a terrible habit to say "I have the controls" and let go of all of them except yaw.
I get all that and understand the logic, but both of your anecdotes are when the rotors are turning. I am not. What gives me the extra chuckle is when they are afraid to hit the SAS/Boost button before spin-up, but then have no issue swapping hands so they can write down a clearance right before taxi. There must be a caveat in NATOPS I'm not familiar with.
The deprogramming happens fast enough, though. They figure out that no one else is going to adjust their BARALT for them or set their RADALT pipper.