Got pulled over for tint once myself and learned fast that cops can hit you with a fix-it ticket on the spot, which turns into a real fine if you don't comply. Most states do fine for illegal tint - anywhere from $100 to $300 depending on where you are - and some pile on extra costs if you have to remove it professionally. The catch nobody mentions is that some states require you to remove it within a set window, or the fines keep stacking if you get stopped again.
Here's the thing though: documentation matters way more than you'd think. When you got the tint done, the shop should have given you paperwork showing the VLT (visible light transmission) percentage they applied. Pull that now and compare it directly to your state's limit. Don't rely on what the tint shop told you was "legal" - some installers are sloppy about state rules and just go with what customers ask for. Your state DMV or highway patrol site will have the exact numbers, usually listed separately for front, side, and rear windows since the limits differ.
If you're already flagged by one cop, getting stopped again raises your risk. Either get the tint removed before the next stop, or have that documentation ready to show you're within limits. If the paperwork shows you're actually legal, keep it in your glove box. If it shows you're over the limit, don't wait - remove it now rather than collect citations.