Like any other event where people from far and wide flock to a single location, Parintins too has its share of pickpockets. I did not hear of any muggings .. the place is safe in general. Just be careful, in general .. and everything should work out fine.
Parintins is a safe town, but as in any situation in shich you are among crowds, be carefull with pickpockets. No major anoyances or violence is expected.