There isnt any link needed. If you are using the tesla app, all that data is going to tesla. They definitely are recording everything that goes on with the powerwalls (they have to, to present anything to you in the tesla app).
Its very common for any access to IT systems to be logged, so not sure why you think tesla wouldnt be logging every access to the powerwalls.
As far as warranty support, like most things it would depend on what happened. The warranty on the powerwalls specifically has different warranty periods "if charged from solar" or if charged from the grid. There is also no reason for a homeowner who didnt self install their powerwalls to log in "as installer", so (for example) if someone messed up settings in there, or settings didnt stick, or it stopped working properly and a person called for support, they would likely be hit with an invoice for services.
As I said, everyones risk tolerance is different. You have chosen to take the actions that make sense to you, and thats great, but no one needs to prove that tesla logs everything, nor prove that any company will charge for issues that homeowners create by doing stuff "they are not supposed to".