In all the years dealing with Amet or Digesett whatever they want to call themselves, I have never been shaken down and have only been stopped when I was actually in the wrong, I may not have liked it but, every time it really was my fault. The Policia nacional is another story, They were always looking to make a few bucks by stopping the gringos whenever possible but not so with the Digiset. I was never written a summons except one time in Santiago about 8 years ago, So I really dont believe they are trying to single out tourists, especialy in Sosua, They stop way more Dominicans than Tourists there, thats a fact.
This has been my experience.