Signs and the Wrong Type of Persuasion

Confessions of an Efficiency Nazi:  I hate it when people want to try flavors in ice cream, gelati and yoghurt stores before they buy.  Especially when there are a lot of people waiting.  It’s a $5 purchase people.  Wanna take a guess at what banana flavored ice cream tastes like?

My favorite gelato place decided to help this problem by explicitly stating that you could only try 2 flavors.  They installed this sign.

Except, anecdotally, I think it backfired.  It seemed to have created more tasting.  It’s given everyone permission to taste.  When people see the sign, what they read is “Please taste 2 flavors before buying”.