We should really hope for a more efficient cubing timer to be made that can prevent mistakes like this. Something that would work something similar to pressing the "lap" button on a normal stopwatch. I'm imagining it would work like this:
1. Competitor starts timer, removes cover on their own. This starts the inspection timer.
2. The competitor inspects, then puts his hands on the timer again. When the hands are removed from the timer, the inspection timer stops and the solve timer begins.
3. This goes as normal, the competitor solves the cube and then puts his hands on the timer to stop the solve timer.
This is great not only for eliminating human error, but also to give the competitor a live view of inspection time so they can get more information than just "8 seconds" and "Go!" Maybe this changes the layout of inspection drastically, but I think it would help to prevent human error. I'm sure it happens all the time, we just don't notice it since it isn't a WR solve.
Granted, I don't expect this timer to just fabricate itself, just thinking out loud here. But with the discussion of a possible new WCA-specific timer from speedstacks, maybe this could be incorporated somehow.