Somewhat related: Some of the older (maybe still current?) Call of Duty games would straight-up ban you if IDA Pro [1] was open on your computer, regardless of whether you were reverse engineering the game or not. Good times.
"...there was a time when anyone could have debugging tools. There were even free debugging tools available on CD or downloadable over the net. But ordinary users started using them to bypass copyright monitors, and eventually a judge ruled that this had become their principal use in actual practice. This meant they were illegal; the debuggers' developers were sent to prison...."