That's DeVries' option of choice.

Personally, I fostered contacts among the penal system and the like, found convicted murderers and rapists on death row, and got some time with them in an isolated location. I'd drain them down to 1 Essence, then let them move along to their well-earned execution. I also took the time to Mind Probe them to find out if I was about to drain an innocent person wrongly accused, or siphon from an already-black soul.
For day-to-day blood, I made friends with DocWagon, street docs and so on for blood packs. Made my Lifestyle more expensive, but that's the smallest of prices to pay for a character with Regen and so on.
I doubt most Vampires go to such lengths, but I felt relatively guilt-free. No propagation of the infection, no innocents harmed.