wrote:
I had an interesting experience the other day. To some degree I was testing
the theory that a local Class-C facility would invariably vector VFR aircraft outside
the lateral boundaries of their airspace. I've seen this at a few different airports
where I transition through with flight following, but underneath (or overtop) the
vertical limits.

If you really meant to ask "where are the regs?" I don't think you'll
find anything specifically about flight following in the regulations.
Look for "VFR advisories" in the AIM. That's the official name for what
we informally call flight-following.

I think Steven said it best (paraphrasing): don't ask, just tell them
you're terminating radar services.

Dave