I've combed the net and people contact me through the article. I've had parents who have told me that they've flown halfway around the world with formula for the whole journey and they have not run into any problems with security.
What has been a problem is the age of the child. Once they hit about age 3, security can get sticky. What was allowed on one flight, just a few months later is not, which can be confusing to kids. But those of you with small, formula fed infants seem to be fine.