Pumpkin was actually pretty well behaved throughout the meal. This may have had to do with the fact that her lunch was a teddy bear shaped pancake with chocolate chips, syrup, and icing sugar, but she ate fairly quietly nonetheless.
While my SIL was in the washroom, I was left to my thoughts, and considered making dining out a more regular habit such that Pumpkin can continue to build on her existing restaurant etiquette repertoire. That was at least until I glanced over at her and saw her sucking up the icing sugar off her plate with her drink straw like some sort of disoriented cocaine addict.
I have now replaced my visual of future family restaurant dining with an image of child services interrogating me about where Pumpkin learned that behaviour.