The US authorities will enver know if you've visited Cuba unless you either tell them or you are likely to be having travel arrangements monitored by them for other reasons! Your passport won't be stmped by the Cubans on either entering or leaving - I'd love one but it's never happened. On entry, they stamp the 'return' half of your visa and this has to be surrendered on leaving. You will have no offical record of ever having entered Cuba - only wonderful memories!
Nor have I ever heard of any non-US national, even if a frequent visitor to the US, having problems. Cuban friends have said that the Cuban authorities apparently do take a particular interest in Cuban ex-pats who try and re-enter on anything other than an infrequents basis but given the attitude of most of the virulantly anti-Castro Cuban ex-pat community, especially in Florida, and the way they have tried to fund subversive elements, this is only to be expected. The UK has always kept a special watch, as does the US, on anybody they think might be implicated in terrorist activity.
Ordinary tourist visitors generally will only be asked for details of their return flight home and to declare on their entry visa where they will be staying. They don't make a note of your ticket details - simply check that you have one - and I've never actually stayed at the hotel I name on my visa! I always stay with a local family in casa particulare but invariably put the Casa Grande hotel on the visa because I don't know which family I'll be staying with until I get there. It's never been questioned despite the fact that the family has to keep an official record of the visitors who stay with them, including details of your passport no etc - these records are never cross-checked, or if they are I've never been stopped by immigration officials telling me I lied on my visa on previous visits.
SM
