On Thu, 13 Nov 2014 06:17:16 -0800 (PST), TimR
wrote:

Graphite is electrically conductive.

House locks don't care, at least at my house there's no wiring.

Automotive locks are a different story. There are lots of connections in both door and ignition locks. I'm wary of introducing another failure mode.
The switch is not the lock. Your ignition switch is often a good foot
from the cyl. In the car door all of the switches are generally quite
a distance from the cyl. I've NEVER seen an ignition switch or
doorlock switch fail from any lubricant put into the cyl and doubt you
ever will either.