For the most part, I think it just comes down to using common sense. There is no “absolute” with this type of stuff. Most of us try to give a thorough inspection, but leave the house for the most part just as it was when we arrived. Sometimes stuff happens though.
A good example that is oft debated is the famed garage door reverse pressure test. I’ve seen many posts here and on Facebook about ticked off sellers when the door was damaged by an inspector attempting to perform that test.
It is not your job to further the damage. OBSERVE and report, those are the limits. Pulling a soap tray off the wall or smashing a tile (which is absurd with your fist - at a bare minimum you’d bleed all over the bath, probably break your knuckles) is not observation. It is destructive inspection right out of the “Holmes on Homes” playbook.
Here’s me punching and smacking the concrete exterior covering material.
You must punch like this.
I flush three baked potatoes down the toilet to make sure that the system is operating correctly.
Possible narrative…
The toilet was unable to handle three normal sized baked potatoes at one time.
Recommendation: Don’t shit out more than two normal sized baked potatoes at one time.
You may need to see a gastroenterologist
I only use the finest Idaho russets for testing. Still healthy in the gastro department.
I throw rocks at windows to make sure they are tempered,
You don’t carry a hammer like the rest of us?
Its far more interesting with rocks, sometimes they bounce off, sometimes they don’t.
Wow, that seems like a lot of work and time involved. First, you have to be hungry, then you have to find a local Wendys, eat 3 of them and wait. Ain’t nobody got time for that. Maybe extra butter can help speed up the ole slip and slide?
No, no. I don’t have them pass through my system. Just three Russets, straight in the bowl and then a flush.
I tried the bucket of golf balls test for a while. It was too much of a hassle to sneak into driving ranges at night to collect inventory.
Oh, I see. You’re cheating.
The golf balls, man you’re a trooper. I don’t think I could swallow one of those. Plus, you need to wash them or they taste like grass and dog poop.
I need more information on the size of the baked potatoes before offering an opinion on the efficacy of that technique. I agree that baked Russets are the most realistic. Yukons are too firm for a good approximation of actual use. However, all baked potatoes firm up as they cool, so you need to use hot ones for the most accuracy.
On a slightly more serious note, I don’t pound on bath walls, but will rap them with my knuckles. I have found many loose tiles that give a hollow sound or click when tapped. And I have identified soft areas the same way without ever actually punching a hole in a bath wall. Since I am under Murphy’s law, if I punched walls, I would punch directly on a stud and break my hand.
In relation to flushing toilets, I flush them in an attempt to get them to leak. I’m trying to get things to fail.
A few times, I have drained master bedroom whirlpool tubs and each leaked and damaged the drywall ceiling below.
This is a good thing.
Professionalism should rule our actions and SOP. Hopefully, we all cleanup our “messes”… 
So if this happens and the homeowner expects the inspector to pay for the damage, how do you recommend the inspector handle this?
In my case, I have Elite MGA. I’m always concerned about this scenario and it sounds like you feel this would not be my fault so I’m not liable for the damage? When I advise my insurer (Elite MGA) if this ever happens, Elite would be contacting or corresponding with the homeowner and letting them know that I/we are not at fault?
I ask because I have no lawyer and no financial cushion. I hate wincing every time I turn on a second floor tub. I wouldn’t want my rates to rise because of a claim that arose just for doing my job 