Okay, so, as far as i know, Unity work as following:
If you are using the free license, you can ONLY earn around U$ 100.000 per year, right? Obviously i am not going to do that, but i was just asking myself what happens if you do not obey, and continue using a free license without buying a better one. I also wanted to know how do Unity knows what did you win. Do each project of the devs have an ID or something that you can track and discover how much it sold?
Well, you’d be breaking the law, and Unity would be entitled to sue you for breach of contract. As part of that lawsuit you might be forced to show your accounts documenting how much revenue you made. If it’s in excess of $100,000 the court will decide on what happens with that excess revenue.
How do they know? Because Unity employs smart people who know the games industry. They know which games are made with Unity, they know which have been featured on Steam, or iOS, or Google Play, and what the selling price was. So it doesn’t take a genius to discover those that are still using a Personal licence but clearly exceeding the revenue cap.