It has been my experience that Latin Americans are very generous with their time and energy. They have really good intentions and will almost always say “Yes” or “Claro que sí” to most requests.
Their follow-through, however, is complex. (See my previous blog: “Love the one you’re with ;-)” ) Previous commitments will not trump current activities.
Yes, almost always means “maybe, if nothing else comes along”. So take their “Claro que sí” with a grain of salt (and maybe a shot of tequila?)