NEW: Tennis star Kamil Majchrzak is looking for a young boy who had a hat snatched from him by a grown man at the US Open. Majchrzak was seen trying to hand the boy his hat when a grown man took it and stashed it in a bag. "After the match, I didn't record that my cap didn't get to the boy ... Could you help me find the kid from my match?" Majchrzak said on IG.