When I was at the border crossing between the two countries in Dajabón, Haitians and Dominicans were going back and forth between the two countries by walking under the bridge (guards were on top). Before coming up on the other side of the border, they had to pay a fee, which presumably covered the costs of the guards above looking the other way. It's much like the border between Guatemala and Mexico.
What was interesting about the economic situation in Dajabón was the Haitians who were allowed to cross the border each week to sell their goods in the market on the Dominican side. So many of the goods that they were selling were donated items from the US and international community, goods which they had little need for and were instead trying to sell. It was honestly disgusting the amount of goods purchased in the US and then discarded or donated that ended up on Haiti. We all know we have a consumption problem but it was awful to see where it all ended up. We could appreciate the ingenuity of the Haitian people who were able to take relatively useless donated items and sell them for some profit to Dominicans who had some interest in the goods. At the end of the day though, it's not the best way to help a people in need.
The other interesting visit along the border was to a free trade factory. The factory manufactures shirts for the US market. The Dominican-owned factory is located in the Dominican Republic so that it can take advantage of CAFTA-DR, but most of its employees are Haitians. The Haitians enter through a back door to the factory and therefore never have to go through customs. They then leave at the end of their shift. The factory provides much needed jobs for many Haitians. The jobs are better than those found in Haiti, better in pay and in work environment.
I'm not against improving security along the Haiti-Dominican border but to do so in a way that does not take into consideration larger forces at work in the area does not seem to be the wisest approach.