Wait one sec, the VK DOES NOT KILL ANYONE WHO USES IT. Whoever said that just made it up. It does nothing for non-Belmonts (as stated in the DoS library I believe). it only takes the life force of non-pure Belmont's who un-lock its power, like the Morris's. Nowhere does it ever say it kills anyone else.
And I doubt the Morris's ran away, they didn't go to the U.S. until one or two generations before Quincy. It is pretty apparent that the VK is handed down father to son, how else would it be wielded by some with the name Belmont from leon down? If given to a daughter the name would change (another reason legends is full of fail). The Morris's split off between Trevor and Christopher (don't remember where I heard that, a timeline or an interview with IGA, not sure) and while still having the ability to use the whip, didn't for hundreds of years. So when they needed to use it, they had to do a ritual, because that part of the family had been seperated from its power for so long. The life force drain is also due to this, I bet if it stayed in the Morris family's hands long enough it would work normally for them.