I would agree with Larry re Belize City. When you get off the ship you are in a compound that is set up like a bazaar. You can see lots and spend money there! If you want to leave I would suggest an excursion, immediately outside the compound is not appealing. One couple on our ship (2 years ago) went out and turned back after 4 blocks - too many beggars, not a plesant place to walk and a police officer suggested going back too!
As for ID this year I noticed all ports suggested ship card AND government issued photo id. We needed it a San Juan, St. THomas and Nassau. They only looked at those people over 18. This is new as in the past we only needed the ship card. I was also told that by next year they may want passports, not any other photo id (e.g, drivers license not enough). Things are changing!