Fake flowers from in-laws after our baby's birth.

Hi ladies,

I wanted to get your opinion on how to handle this situation. We just had our son a few days ago and we just received a box delivered and it looked like flowers, we opened and they looked like real flowers, we assumed they were. My husband calls his stepfather to thank him and his mother for the flowers and he told him they were fake. My husband laughed it off and thought it was weird. I was mortified at the gift and was very offended. I have never heard of someone giving fake flowers to congratulate someone for anything. Is this normal for American culture? How would you handle this?