It's as simple as this: if someone digs in his pocket, and puts his money out there for you to take, you are NOT required to accept it.

And even if you do accept it, you are perfectly within your rights to hand it back.

I also know for a fact the sender can get ALL his money back from Western Union if it's not been claimed yet by the sendee.

Jack

PS: And even if you took the money from Western Union, you're still within your rights to send it back, LESS your charges for sending it.
EG: If you get $1,000 for the dog, and it costs you $15 to send it back, then the man gets $985.
.... You do NOT have to pay anything extra for his failing to tell you it's illegal for him to get a dog.
.... You're not required to know the laws of every country in the world; HE'S required to tell you the laws of his country.