A Word of Caution

I love these little plastic cups that come with sippy lids and protect my floor from spills. I love that when my kids want chocolate milk, I can pour in milk and Ovaltine, pop on a lid, cover the hole with my index finger and shake, no spoon required for stirring. However, today I discovered their Big Downside. The diameter of the top of the cup is exactly 2-7/8 inches. It so happens that the diameter of the disposal side of my kitchen sink is exactly 3 inches. Do you see where I'm going with this? The cup in the sink managed to fill up with water. The weight of the water caused the cup to sink through the black protective flap ringing the inside of the drain, and plummet down to the bottom where the disposal is. I was fortunate to discover the source of the stopped-up sink before turning on said disposal. It took two pairs of needle-nosed pliers, lots of elbow grease, and ten minutes of grunting and wishing that I swore, to pry the blasted thing back up over the flap and remove the cup.