I had to go into Havana/Marina Hemmingway, 5 yrs ago, because of boat problems. American passports, boat and even a second gereration US/Cuban as mate.
They were delightful, did not stamp our passports because they knew it would cause problems with bozo George W.
A Cuban Coast Guard officer congratulated me on putting the boat on the customs dock under sail and got me a Cuban Navy mechanic within an hour.
The head official offered to get a government car to take the first mate to meet any members of his family still in Cuba.
US paranoia is misplaced and incorrect...but do take lots of $s in small denominations the credit cards do not work.