Please visit my LinkedIn article posted this morning for a brief explanation on this issue:
https://www.linkedin.com/today/post/...?trk=prof-post
This question is raised often and debated much amongst lawyers focusing their practice on employment-based immigration. This morning, I have a call scheduled with a corporate client who is considering the legality of accepting a volunteer in their for-profit IT business.
Mr Khanna's amazing knowledge in immigration law helped my wife to get her H4 visa.