Why are you implying the thiefs are Roma? From what I've read and found out from local incidents it's normal people from Romania, Poland, Bulgaria and so on
Because the ethnicity of those from Romania, Poland, Bulgaria is usually Roma/Sinti, even though it's usually not politically correct to say it. Just ask people from Eastern Europe.
No, those usually just live in their camps and go begging, but they sure as hell don't drive for 1½ days to Austria to rob bike stores, as opposed to regular Polish/Bulgarian/Romanians. These groups are sometimes picked up, and just because racism against Roma and Sinti (who are actually stationary most of their lives) is still socially acceptable doesn't change that