When we flew in September, just before the latest rule change, on the way into the airport to depart for MCO my ds had a sippy cup with milk in it. It was about 5am so of course he didn't want it yet, so it was full. When we got to security, of course they told us we had to chuck it. (I only brought in the hopes they would let it thru because the TSA site said milk and formula is allowed if you have a small child with you...not always so, apparently). Anyway, I told ds we had to throw it out and he kept saying, "No, Mine!" and drank part of it. He'd stop for a minute and I'd try to take it from him again and he insisted on drinking it because he was just being a possessive 3-yr old (lol). Anyway, this was all taking place right in front of the TSA agent. She looked apologetic but still wouldn't let us pass thru, even after he had swallowed 3/4 of the contents in that sippy cup. So yeah, they can be very strict. Even if it doesn't make sense.