The ICC investigation, over the course of a year, identified over 800 violations, most involving making unauthorized tows --- often from places they had formerly had contracts but no longer did, or places where they claimed they had contracts but where no contract was on file with the ICC. Which squares with the general take on Lincoln Towing, which is that they're just a bunch of people in tow trucks looking to tow as many cars as they can.

Lincoln's defense: the ICC never told them they were violating the law.

What I learned from reading all the ICC filings: in Chicago, you need to file different contracts to tow on a "patrol" basis (where the tow truck spots the unauthorized car) vs. a request basis, where the customer asks you to have a car towed. Lincoln Towing didn't care about the distinction; the ICC did.

Also, they had drivers without licenses.

Honestly, I doubt the other Chicago towing companies are much better.

Their Wikipedia page is pretty funny; it's pretty clear that someone with an interest in Lincoln Towing has authored chunks of it.