From the words of the Cruz campaign, they notified all precinct captains. Whether the captains actually made mention of it appears to be in question according to your account. The fact remains is the campaign admitted sending the messages to them all.
Two different questions. One is, did Cruz try to cheat? Another is, was the outcome affected?
I should add this:
The caucus rules were that it would open with the Pledge (and a prayer), electing a permanent chair, and then immediately going to time-limited appeals from candidate reps.
In a couple of cases, I spoke to people who said that someone did mention the ‘news’ privately, but that the Cruz rep had already spoken and no one attempting to bring the ‘news’ to everyone’s attention.