It’s all strategy. Experianced observers know this but you can only put up with so much abuse. This is where it’s critical to have the support of the sponsoring club. Before you can have a hard line on rules you have to know the trialsmaster will back you up.
Nothing makes me less enthusiastic about observing than knowing if I make a hard call someone in the club organization will overturn it because a “top” rider whined until he got his way. If calling to the rules is not supported then it’s not worth the effort and everything is called like a beginner class. “Good job”, pat on the head, NEXT!
Years ago I observed a US national and at the observers briefing the NATC rep went into a long diatribe about how everyone was there to have fun and not to be too strict on the rules. One of my buddies raised his hand and said, “So which rules do you want us to ignore?” Pretty much summed it up.
Partial enforcement of any rule is how you end up keeping bad rules. It’s also the fastest way to make a sport unfair.