Halifax tourism website says "Some people who visit go back with a smile on their face..."?

Question

"...the rest just don't go back."

Is this a threat of, "When you visit us, smile, or we'll kill you"?

Answer 1

Yes.  It's part of the mission statement for the Canadian Tourism Board.

Answer 2

I suspect this is an ad produced by the Province of Nova Scotia Tourist Department.

It is not a threat - the intention is to communicate that most visitors are very Happy with their experiences in Nova Scotia.