What Would You Do?

While we were at the Aquarium Restaurant last week we sat next to a couple of mommies and their children. The kids ranged from about 2 to 10 years old. The older kids ran around the restaurant looking at all the fish (as did mine!) The mommies and the 2 littler kids stayed at the table. They looked like they were having a nice mommy's day out, until one of the little ones started fussing. Not bad fussing, just a little bit of whining. I heard the mom threaten her child with what sounded like "hot sauce". I thought sure that I misunderstood because I have never heard of punishment like this before. When I glanced over I saw the mom with a dropper that she was putting in her child's mouth. Obviously the little girl (about Hannah's age) was used to this because she opened her mouth like a little bird, all the while crying "It's hot, it's hot!" The woman then apologized to her friend for the noise. I was so infuriated and stunned but I didn't know what to do. I mean, what could you do? It is so passive-aggressive to just shoot her dirty looks and if I was braver maybe I would have said something to her. Is it an over-reaction on my part to be so upset by this?