The way they are arguing the airspace was that sitting on the ground you are class D. It isn't until airborne and above 2500ft agl and/or 4nm from the airport you hit C.
That's wrong as the AIM shows the class C as being centered on SAT. If you were at Randolph, he would be correct as that is a satellite airport and will have Class D airspace under the C, and you could stay in the pattern there and never touch C.
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