If you make a copy of something -- and keep it private for as long as you live -- as instructed...that's not going against such instructions.
As for your claims of the "3 witnesses," Godzilla's done a great job in other threads dissecting such Lds claims. (Perhaps he can jump in)
Problem is they never saw the plates - their ‘story’ relates to visions. Why have ‘visions’ Norm, if there were real plates in existence. Testimony also exists that Smith never even used the plates anyway, that the ‘translation’ came from his peep stone, with the ‘plates’ secured elsewhere. The “witnesses” didn't see the “plates” at the same time either. Simple fact is that these same impeccable ‘witnesses’ were later called liars, counterfeiters, thieves, etc. by Joseph Smith himself.
Let us also not forget these same witnesses claimed other mormon splinter “prophets” were the true prophets as well as testifying to a greater revelation from them than smith.
Their testimony in the front of the bom is nothing different that the ‘testimonies’ commonly placed on the various snake oil cures of the same period.