I knew someone who's parents did a variation of that. They took pictures of their baby when it was a year old. It was in a floating basket at a nearby small river. A recreation of the Moses story. Wrote on the back something to the effect on such and such a date we found a baby. We named him Robert. We feel very blessed by God.
They had a whole production at his birthday party when he was 12 to back up the story. They didn't own up to it being planned for a few hours. I was one of his friends, and he seemed overwhelmed by the idea. No huge reaction other than adrift from everything for a bit. I think it actually stuck in his mind for a couple weeks. As if he thought his parents weren't his parents and decided to lie to him when he didn't take the news well. So a puncture to some basic trust for awhile. I don't know if any permanent damage was done, but with some people it could have.