The draw backs of teaching your kids sign language

To make life easier on Scott and I we taught our kids very basic sign language so they could communicate with us before they were able to talk. These signs included "please," "thank you," "more," and "all done." It has really worked great for us and has really helped lessen the whining when they are trying to tell us what they want and we can't understand what they are saying. Today Connor found a way to use it against me. He doesn't really use sign language anymore since he can clearly tell us what he wants but we still use it with Olivia. We were at my parents house and the kids each had a bowl of chips. Connor ate his and asked for more. I told him no and that he didn't need anymore snacks. He asked if he could have sissy's snack, I told him no. A couple minutes later I looked over and he was tapping on Olivia's head to get her attention and signing "more" to her, asking if he could eat more of her chips without me knowing. That kid is so clever it frightens me. I firmly told him he could not have anything else to eat, but in my head I was thinking, "Nicely done, son. Nicely done." I will have to keep my eye on that boy, both eyes.