quote

time? In other words, if you blunder into Class C while talking to
Center on VFR advisories, either perhaps because they forgot to hand
you off or because you wandered off altitude and they didn't notice,
would you be ok, or would you be busted?

It means the ATC facility controlling the Class C airspace. Airspace
delegated to approach control facilities tends to be significantly
larger
than the Class C airspace contained within it. While Class C airspace
has a
radius of ten miles around the airport the airspace "owned" by the
TRACON is
probably at least thirty miles radius. If you're still on Center
frequency
as you approach a Class C boundary it's because Center forgot about you
or
you missed a frequency change
quote

But would he be in violation of 91.130(c)(1) in that scenario?