Motivation? Just to get a little sympathy from a lot of credulous folkies. All those "last goodnight" type ballads are attempts to present a selection of scoundrels as upright noble citizens wrongly found guilty by the wicked authorities, or forced into a life of crime by the nasty powerful men ( fancy coming up to someone "in a manner rather rude using vulgar words of language" eh, enough to turn anybody from the straight and narrow). Robin Hood, McPherson, Captain Kidd, Pretty Boy Floyd, Armstrong, they were all up to it, and now this whining Black Veil type. Pshaw, I say. Give me Sam Hall anytime, he took it on the chin and spat in their eyes.