What I don't get is the definition of "volunteer" and have had many misleading definitions. For example, if a person helps out at a fundraiser, do they need a work permit? What about teaching a class at Holy Cross? What about helping at Saga a couple days a week? What about fundraising activities for Neighborhood Watch? Someone said that you don't need a work permit for non profit groups, but I am not so sure of that.
I asked Immigration last week again and this time they said that the specific organization must complete a letter spelling out your duties which you must submit with the application which has to go through an approval process (not sure of the time frame...).
I would wager a bet that there aren't too many non USA citizens volunteering in the US, but plenty who have been working for lower wages.