Most "wrong" bunker calls, even ones I think are ridiculous, have as many people arguing that it's the correct call. Refereeing Rugby League is not an exact science, unfortunately. Some of that could be improved by better rulemaking and processes, but some we just have to accept that the referee is there to make a decision that he feels best reflects the rules and spirit of the game. It's why I prefer the referee to decide whether someone was obstructed rather than rely on strict guidelines about 'inside shoulders' and whatever else.
For me, the far bigger issue than incorrect bunker decisions is the sheer amount of timewasting with video reviews, killing the flow of the game and crowds enthusiasm. This trial is a good first attempt at reducing that, I'm glad to see it, despite the exact rules of it not being how I would implement it.