My daughter once told my husband that I hit her on her face, hard. She was about 2.5 years old at the time. She said it three times to him in the space of about 24 hours. It never happened. I have ZERO idea where her little brain conjured up that image.

These things happen. Maybe it was a dream? Maybe it wasn't, though. Either way, unless it's repeated reports of hitting from dad, or unless you start seeing marks on the kid, I wouldn't say or do anything. Unfortunately, spanking is legal.