If one release a hobbyist blueprint to put an electric motor on a bicycle and then a megacorp uses that (without any due care) to release a mass-produced e-bike

If one release a hobbyist blueprint to put an electric motor on a bicycle and then a megacorp uses that (without any due care) to release a mass-produced e-bike marketed worldwide which ends up catching fire or otherwise producing injuries due to a design flaw: - Why should one be held liable or have a legal obligation to the customers of the megacorp? - Why would one even be afraid of being sued by the customers of the megacorp? (other than if we lived in an otherwise draconian society)