[Chris is me]

I think you fundamentally misunderstand what FIRST and FRC are about, and what the mission of this program is.

FRC is not about finding the best students in the world / North America.

FRC is not about having a competition where those that refuse or don't utilize mentor help are put on a "fair" playing field with those who accept mentor help.

FRC is not an "adult hands off" competition where students have to learn and apply complex engineering principles entirely by themselves.

FRC is a competition where students and mentors work together to solve the tough engineering challenges that come with building a robot. Teams in this competition interact with, compete with, and help a variety of other robotics teams of varying backgrounds, budgets, and resources in order to achieve the common goal of inspiration. Above all else, FRC exists to inspire students to pursue STEM careers and inspire the greater community to recognize the importance of STEM.

The key elements there - the student-mentor partnership, the inspiration, interaction with differing teams, are all hurt by your proposal. Banning mentor involvement results in less functional, and thus less inspiring, robots. Banning mentor involvement puts more burden on students to already have the skills they need to help an FRC team; quite frankly the students who walk in knowing how to machine / design aren't the kids that need inspiration. In a quest to make the competition more "fair" (a loaded word which in this context means "every team is run the way [you] want them to be"), you reduce the diversity in team backgrounds and resources. This may seem like a "good" thing at first, maybe, but the result is more similar robots, less chance to be exposed to something new, a lower target for students to be inspired by and reach for...

Lest you feel I'm posting merely to defend my own ability to play with robots, I can assure you, that's not my intent. I work tirelessly with my team to get as many students engaged and involved as I possibly can. These rules would get in the way of how I've been able to do that.