they are already free to do that.
—Comp time is more regulation.
Hmmm, you have the whole thing backward
Thus, to answer your question, you are not permitted to use comp time for a nonexempt employee who works more than 40 hours in a single workweek. That is true even if the employee requests or expresses a desire to waive overtime pay in lieu of comp time. Only public-sector employers are allowed to provide comp time to nonexempt employees.
http://www.hrhero.com/hl/articles/2013/04/23/comp-time-not-an-option-for-private-employers/
http://www.nolo.com/legal-encyclopedia/wage-hour-laws-faq-29118-4.html
Yeah, of course you’re right and I knew that.
Suitably chastised.