Moderation is one thing you mentioned. Adding a couple drops to one of the food items for a "treat" is different than using a bottle of dye for the meal. It only takes 2-3 drops to colour the milk for instance. I would be using green foods instead for the day so cucumber and lettuce for lunch etc.

My gang is young and really have no concept of St. Patrick's day or any other day for that matter. I tend to totally gloss over a lot of the holidays as it interferes with our play, lol. Mine would not appreciate having their meal altered in any way and with lids on the cups the green milk wouldn't be seen.

We are experimenting with rubbings today. I printed out shamrocks on white paper and they will rub them over the texture plates with green crayons. While it is still a St. Patrick's day activity it is about the texture plate rubbing not the holiday.