Not only would this protect innocent citizens from the abuses of bad cops, but it would protect good cops from the claims of bad citizens who falsely accuse them of wrongdoing.
Not only are we seeing just how widespread and common these abuses are, but the current climate has the public quick to accuse and to raise a stink about cases where they have no standing.
A body cam might have prevented the Ferguson riots and all the aftermath (since the cop was exonerated in that case) just as it might have prevented the cop in SC from shooting a fleeing motorist in the back.
Here at home, though, it would have prevented an otherwise outstanding young cop from being raked over the coals for a non-lethal takedown which resulted in the death of a 90 something year old crazy guy. (His injuries would not have been fatal but the guy and his family all refused medical attention)
Of course it would be an expense to arm all cops with cams but I feel the good this would do both cops and the public would far outweigh what it would cost to buy them.
"The difference between genius and stupidity is that genius has its limits" --Albert Einstein