A Natural Table Salt That Stands Between Children and Almost Certain Illness" - Morton's Iodized Salt, When It Rains It Pours (Child Life, Feb 1926)
The pattern
This still is filed under Problem-agitate-solve.
Define
Name the problem, make the cost of leaving it felt, then present the way out as relief.
Mechanism
Tension then release. The offer is not an interruption. It is the only door once the cost of staying is clear.
Verdict
The problem is known but not yet urgent
Why it works
Combines a strong fear appeal (illness and possible deformity) with an incredibly easy, low-friction solution (just use this salt). It leverages the existing brand equity of Morton's standard salt to introduce the new iodized health variant.
Steal this when
You are introducing a health or safety improvement to an already trusted everyday product.