Basically, come up with a list of trigger words and then work them into innocuous sections of text in a random manner. That way "they" can't filter out the text being sent.
So doing the basic math in my head, the chance that this will succeed is... trolltastic (means like 0, since even if it has a chance of succeeding, they could ignore all phone calls from that one hour, also if this is written well, and scalable they can just spin up more workers -- so unless you can get like 20 billion phone calls I doubt it'll be an issue)!
However let's let the fun begin!