The young American boys were actually an uncle and his nephew. Their father/grandfather refused to put on tefillin. The more I tried, the tougher he got. He was becoming angry with me, so I changed the subject.
One of the boys started to play in the bottom of my tefillin cart, so I wheeled him around a little. The other boy saw it so he quickly jumped in, too. I pushed them in circles and back and forth. It was surely the highlight of their trip to the Kotel. Their father saw how happy they were and took a bunch of pictures of them. Then, he came over to me on his own, and put on tefillin.
I used his camera and took a couple of very good photos of him and his adult son with tefillin on. Their big smiles will remind them how nice it is to put on tefillin at the Kotel.
You never know what works. We are not allowed to push because they can become angry, but we are allowed to pull, because, deep down they like to be brought in.