It is your responsibility to know and be in compliance with the tech rules of your class.
It’s not a good idea to rely solely on your motor builder’s word or work performed and expect to be in compliance with 100% assurance. I’m not pointing fingers, but engine builders are known to push the envelope as far as they can, it’s what they get paid to do – but sometimes that results in a non-compliance issue, albeit not intentional – but non-compliance is still going to get you a DQ. It is their goal to provide you with the fastest motor – it’s why you use a motor builder in the first place, and while reputation and intentions are honest and professional for most, there are still those who disregard the tech manuals and try to get away with things they know will be a violation but believe they won’t get caught, or it won’t be detected, just so they can have the fastest motor at the track.
Again, they are few and far between, and new or unsuspecting racers may get blindsided – or in some cases a parent will be in cahoots with a dishonest builder with full knowledge of violations being made in a misguided attempt to win races at any cost. That’s why tracks/events have to have to hire expensive Tech Inspectors who are trained and certified. That’s also why we have Claim Rules in place – to keep everyone honest. But it’s my experience that a cheater motor will always get caught, so don’t be tempted to “even the playing field” no matter what you think your justification is. It will only hurt your child in the end. If you think someone is cheating and they have’t been caught by Tech, then file a protest or claim their motor.
But chances are, the ones you think are cheating are the ones who are actually in compliance.
Another reason to be fully knowledgeable is if you are DQ’d you have the right to appeal the ruling if you think that a mistake has been made. You have until the following Monday to present your facts. Only someone with a working knowledge of the rules, the motor and any work done by the builder, would be able to formulate a defensible appeal.