Well this is great. You can make all the excuses you want, but he was charged under the immigration law. I doubt you would be arrested if you did this. Ticket, yes. Arrested, no.
And he was released when the proper documents were produced.
"Mercedes-Benz spokeswoman Felyicia Jerald said the man is from Germany and was visiting Alabama on business. The company's first U.S. assembly plant is located just east of Tuscaloosa.
"This was an unfortunate situation, but the incident was resolved when our colleague was able to provide his driver's license and other documents to Tuscaloosa police," Jerald said."
Yes, a legal citizen would have been ticketed for not producing proper documentation. However, my experience with not having my license on me (admittedly a long time ago when I was driving in a swim trunks) and being given a ticket, the ticket was dismissed when I produced my drivers license to the court clerk. The law adds detaining someone who might not belong here until proof can be offered that they do.
As I said above, German police would do the same to you if the situation were reversed. Even more so as a drivers license is not considered legal ID in Germany and they will want to see your passport for identification and your drivers license if it is traffic related. All Germans carry a Personalausweis (ID Card) and, if they drive, a separate drivers license. The fact he left his hotel room with neither in his pocket is odd. And you cannot even get a hotel room for the night in Germany without producing a way to pay and your passport.
And my feeling on this is his boss back in Germany are probably more upset with him for not having his documentation than they are at the state of Alabama. It's very "unGermanlike".