Activations often chase the busiest entrance. For shelf conversion, the more useful signal is hesitation at the bay: the shopper who compares two packs and leaves empty-handed.
Place sampling or demo staff where that pause happens. Give them a single proof point and a clear SKU to recommend. Measure pick-up at the bay for the campaign window, not only samples given away.
When activation and shelf work share the same conversion goal, spend stays focused and results are easier to read.