An organizational mess
I don't blame the DR for the fact that with 15 days to go that schedules are tentaive and tickets are not yet available. As of July 17 many countries were still confirming the number of participating athletes. For example in female soccer a home-home match between Haiti-DR will be held with the winner qualifying for Pan Am tournament. Unbelievable at this late date.
The Panamerican organizing committee (based out of Mexico?) should be held responsible. I don't know many Americans, Canadians, Jamaicans, etc willing to travel to a foreign Spanish speaking country without a confirmed ticket in hand.
Other countries have recently announced participation or withdrawl from certain events. A classic example is that several family members of mine from Bolivia have been planning to come to DR to watch long distance races (5000, 10,000 mts and marathon) where Bolivian friends/family will be participating, but until 18 days before the opening they couldn't find the exact dates of the events, let alone the times or purchase tickets.