I've never touched harder than is needed - maybe different people have different styles.
Of course they do.
It does seem to vary between units - maybe depends how tightly the screws near the front-end are tightened - I think mine had loctite on before i took it apart - have you had yours apart yet ?
No, not yet. Factory freash, 5 minutes of use.
And yes it will vary between units. Component variability alone.
There is obviously direct coupling between the various connection points in the assembly, and likely the offending CH1 cap(s) are in a higher mechanical resonate mode spot on the board compared to the other channels. I used to work on this stuff all the time in my seismic days, physical location on PCB and location to rigid mounting posts makes a hell of the difference. Hit a resonance mode sweet spot and it sings like a bird.
Mine shows significant disturbance on ch1, and only slight on ch4 when tapping the top case with fingers.
Being similar to mine that indicates it's more mechanical mode coupling and PCB location resonance related than component differences.
Really don't see it being a problem.
It was blindly obvious to me in the first few minutes of using it, so I'd say it's a problem.
Tapping the BNC's, ok, every scope has a direct coupling at that point, fair enough.
Whacking the top of the unit, ok, don't do that, fair enough.
But a much touted touch screen being able to generate many division level impulses when tapped is unacceptable, even if some units aren't as susceptible.