Everyone should be able to fix their own things, AND have the choice to leave it to a professional. Only a few things are legally required to be done by professionals, things like asbestos removal.
Things use to come with schematics including devices like Crt TVs that had many thousands of volts with a potential to kill a person instantly.
This whole "omg, the potential of poisoning from a battery or electrocution" (how is it any different if you buy that same battery without the device - perhaps we should ban sales of parts too) is a convenient excuse for manufacturers to make things to be disposable. It has the opposite effect, because the useless device will be thrown into trash and then it will become E-waste with a far bigger potential for poisoning water in some third world country than it ever had by being opened by an "unqualified" person.