The problem: Once you have a microcontroller running a tight loop with lookup tables for fuel and spark, it's very tempting to make it run a tight loop with lookup tables for fuel, spark, and time since license renewal - and there's no outward difference between the two microcontrollers until one of them stops working. This is where regulations can help: if a manufacturer is afraid of a zillion dollar fine, they won't do that, even if the chance of getting caught is low.