Definitely some of that... I think as well that they probably get food donated by the towns, cities, and farms they help to protect. Not in a Mafia "sure would be bad if something happened to this nice farm" sort of way, but in an actual show of appreciation.
Or, at least, most of the time not in a mafia way. There's always Komodo's Marauders.
RE: Worldbuilding Weekend Prompt #16 - An Army Marches on it's Stomach