Your co-worker is correct. Without a doctor's prescription or out-of-state plates, no aftermarket tint, whatsoever below 4" on the front windows.
Michigan Tint Law
That said, I have a very light tint on all my windows, and have never been stopped in 15+ years. On the other hand, my wife had two vehicles with tint, and she was cited and issued "fix-it" tickets for both of them. In both cases, no charge for the ticket, just pay a tint shop to remove the offending film, and take the vehicle to the issuing police/sheriff station for verification to dismiss the ticket.
If you want the tint, get it. Just accept the fact, you may have to pay to remove it, and reinstall, if you want to keep it for the long haul.