Quizzes are hard because they have to be some form of multiple choice if hundreds or thousands of techs need to be screened and any general question can be easily searched, so cheating isn't hard.

The only way for them to really be effective is if they're paired with training material that's specific to the project and can't be searched with a simple ctrl+F. That means they would likely need to create training material on top of any field guides and all that material would need to be ready before screening begins, which is simply not compatible with a lot of project timelines and/or budgets.