Another data point for those with families: I flew into Newark from Brussels in February with my 5-yo. I have GE, and he obviously does not. I went up to the kiosks with him, intending to get the X and then talk to an agent, as others on this board have done. There was an agent walking around the GE kiosks when I did this, and he told me whether or not I had the X, since I had GE and a child along with me, once I used the kiosks, I could see an agent at the front of the line.

This might just be one agents POV, but he seemed like he had seen this a lot, and this was SOP.

PLEASE NOTE: This post is now outdated, since all ages are now eligible for GE. Again, you can no longer walk your kids through with you!