The really important thing for Cuba is to ensure the printed policy clearly mentions coverage for Cuba and medical evacuation. As you know its mandatory to have TI policy which includes medical evacuation in order to enter Cuba, and to have it at hand on entry.
I didn't get asked to show my Policy, but an Aussie couple on the same flight from Cancun (who had been on my tour of Mexico) went through separate gates but were listed on one policy, the wife went through but her hubby got detained when he couldnt show the policy - it was a bit of an ordeal for her to get paperwork back to him - we waited a while has had a shared ride.
If like Cuba it was mandatory to have TI to enter all countries we see much less crowd funding requests or lobbying govt to rescue travellers who are too cheap/lazy to get cover.