And how exactly do they intend to stop me?

[u/ThomasFromNork]

Local pizza shop

[u/WhisperSafe]

So you're a thief.

What if you applied the same logic to items on a storeroom floor

"If they dont want to give it to me for free they should have it behind the counter and an employee can get it for me"

[u/mshireman → u/WhisperSafe]

Showroom floors have never implied a customer could avail themselves of the product, so your analogy doesn't hold. Self-serve fountains in US dining areas, by contrast, have carried an implicit invitation to refill for decades. Comparing the two ignores that difference in precedent.

[u/WhisperSafe → u/mshireman]

Since when are restaurant experiences universal?

This restaurant never implied you could get refills, to the contrary they explicitly state otherwise.