These devices are not "defeat devices". They are tuners. They are used when upgrading to higher performance components like high flow air intake and exhaust systems or engine upgrades. Tuning a motorcycle quite a bit different than it is with a car. Anyone who has installed performance upgrades in their car has had adjustments made to the onboard computer. That is essentially what these device do. If the bike isn't tuned to a narrow set of specifications engine failure will soon follow.