[throwaway219450]

Maybe Peter can comment further, but my impression was that the definition of "work" is normally unrelated to whether it's paid or not, for F/J?

If those students are actually concerned about staying in status, simply saying they're volunteering might not be sufficient.

[proberts]

That's right. Working without pay in jobs that normally are paid could still be considered unauthorized employment.

[mikeyouse]

Thanks - very useful to know that there is still risk for the unpaid ones.