Blocking the internet, if done well, makes it very difficult to get mass distribution quickly. If it's only a few people that manage to get communications working, cheating becomes a minor issue instead of a major issue. I don't agree with the tradeoffs chosen, but it sort of makes sense.

Without being there to see the exact shape of the blocking, it's hard to know if you could get mass distribution through a phone tree system, but if you could, you'd likely leave a huge trail through telco billing.