Just listen to what they have to say and evaluate if it's a good idea. If it is not a good idea, it is not constructive, or not actionable, or if it is not a priority you can voice that opinion.
It is called critical thinking, collaboration and professionalism.
Isolating a new person for having a good idea is being unprofessional and passive aggressive. Using your numbers to psychologically abuse a person just for having a good idea sounds more like prison culture than a real engineering organization.
It also creates a culture of mediocrity which scares away talent, and a breeding ground for psychopathy.
Just do your job, which is to solve problems, not creating new ones. Focus on the problem to be solved.
When you are being paid by a company and acting on behalf of the company, wear the company employee hat instead of the roman politician wannabe hat.
"We hire smart people to tell us what to do" - Steve Jobs.
