Someone from DE pointed out elsewhere in the thread this could be used to avoid paying ppl properly -- classify someone as "volunteering" to be paid a paltry sum with no pension contributions etc to work on tools that benefit for profit corps.
So definitely want to be mindful you don't open the door to tax avoidance and exploitation under the guise of charity.
I know very little about the EU, but I've worked with nonprofits a lot in the USA and there's a lot that are basically corporate cut outs used to lobbying that's a stretch to say is in the public interest.