Funny to read some of the responses, from pro to con, from off topic about breast feeding to regular smoking (heaven forbid someone see a breast feeding baby, the horror of the human body, must learn that the body is shameful).
Anyhow I will put my 2 cents in. We have been on several European cruises and have witnessed some people smoking but have only seen it once on a cruise from the U.S. although im sure it happens on every cruise. We are not smokers and never have been but arenít uptight about it either as long as it isnít near us. I personally wouldnít take ANY chance departing or returning to a U.S. port. Have you been through an airport or a port on entry since Sept 11? Security is tight and itís not worth the risk with anything illegal or that might break the rules. I was detained for quite some time on a flight back from china for some unapproved food.
If stopping in Mexico/Jamaica Iím sure an inventive person could figure something out that wouldnít include the ship. Anyone that has spent time in Jamaica or Mexico realizes these countries arenít as strict and certain things are downright common.