I would be more worried about being ripped off by fellow ex-pats than Dominicans.
the areas of expertise of gringos and dominicans are different. gringos are better at fraud and cheating in general. i still fondly remember female canadian who was a poster here for a long time... dominicans, on the other hand, are very traditional and prefer good old fashioned robbery or murder, with a pinch of extortion. different skills call for different work ethics, so to speak.