Get real close up and inspect it ...use a latex glove
and feel around the COLD engine, then look for oil
on your glove, then wipe off the suspect area and
repeat the exam some other day to confirm whether
there is oil or not.
A small hand mirror and flashlight also can help
a visual insp.
You warranty seems to state that it will replace the
'gaskets' if it is secondary to repairing some other
failed part in the engine.
As per your quote. You can always claim that your
head is warped (not you, tour car..) and it needs
to be replaced or repaired such that the inevitable
is that the head gasket needs to be removed and replaced.
This was the case for an american car I owned 12 years ago
very near the end of the manufacturer's warranty.
My cost $125.. new head and by the way, new gasket...

Let me know how your warranty co. reacts. I'm interested
in how to contact them to see if I can get an extended
warranty for my C280!

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD