This is extremely helpful! Do you happen to remember what line numbers those are?
You're right that it seems too risky a lot of the time -- of course, it would be a lot less bad if you're trying to standby TO a different airport rather than FROM a different airport.
SDC is naturally a safer option. Do you know if there's anything in the GG SDC text that allows the same thing? It would seem kind of silly if you could do it as a standby but not SDC, but wonders never cease
