Your code is deliberately user-hostile. Farmers aren't trying to hack their tractors for the sake of it; they need to hack the parts of your code that prevent them from performing routine maintenance. Replacing a fuel pump is not going to turn a tractor into a rampaging death machine.
You are using spurious safety arguments to justify profiteering. Software lock-outs are being used to prop up a business model, just like the chips in printer ink cartridges.