Wonder what the wording is. If it is more like "-I am brining the embryos", "-ok" it will be hard to prove it. Or if it's more like "It's illegal, don't declare them, look at the customs people smile but don't smile or stare too much". They still managed to ruin her life of course over it.
And I agree with another downvoted poster currently that this was a fuckup on her boss. It's not like he didn't know the current environment. If you hold a J-1 or F-1 visa you don't want to be traveling and crossing any US borders if you can avoid it. It wasn't safe years ago, and it's even more unsafe now. Just going to France to see a performance doesn't seem like an appropriate risk. Doing anything illegal at all, and you're now in jeopardy. You're essentially at the mercy of the State Dept to revoke your visa at any time. If you have lawyers you can fix it in court, but I that is a major uphill battle.