Colleges do not ask for verification. Since it is your personal application, you are expected to be honest about yourself. Exaggerating some activities in the Common App does not help you get accepted in the college. There are other portions of the Common Application which needs to resonate exaggerated activities. College Admissions are professionals who can easily find an exaggerated application from a honest one. Exaggeration is common but honesty in all parts of the application could do wonders.
Hope that helps.