Preval would be regarded overtaken by events or really go crazy if he made such a decision.
However, he would do the right thing if he stopped some countries such as the USA, France, the Dominican Republic, etc from taking advantage of the current crisis the Haitians are facing to humiliate them, even though it is a question of humanitarian actions.I wouldn't see any reason for refusing Dominican troops to come to Haiti, for the military are not only trained to wage war but also to help civilians in crises.
In my opinion, Preval could make such a decision, as the saying goes,"to turn shame into anger or pride", It is so true that the Haitian State has remained indifferent to Haitian problems for a long tme. For example, the Dominican and French governments deported Amaral Duclona to France, no reactions on the Haitian government's side. Thousands of our fellow citizens were massacred in our Dominican neighbors' under Antonio Vincent, no responses from the latter.
French soldiers trampled the Haitian soil about 200 years later after the French and American governments made Aristide leave his country by force, no problems...
Americans occupied our country from 1915 to 1934, and they continue treadding upon our land when they want. From time to time, Haitians have been heard killed or beheaded in the Dominican Republic, and our country stays passive to its sons and daughters' situations.
Since all those events are polical, it isn't a problem if preval accepts Dominican troops trample the Haitian soil for humanitarian reasons.
The Haitian people does need assistance now, no problem...