“On the one hand, this would stop parts – such as the keyboard – from being swapped out for backdoored gear.
Of good grief. Like this is actually a serious threat. If it’s more than 0.1% of keyboards swaps I’d be surprised. The vast majority of repairs are genuine a some numpty has spilled something on the keyboard, or they were crap keyboards in the first place. Don’t get me wrong, hardware has been hacked for nefarious reasons, it’s just not a sufficiently large problem to be a legitimate excuse to prevent repairs.