Publishers have various criteria to identify people who will benefit the most from these free subscriptions.
These criteria usually involve geographical eligibility, profession, tools used on the job, team size etc. Note that one or more of them could be used to identify eligibility.
We, at freemagazinessite.com do our best to ensure that we match the right professionaks with the right free publications. We are successful at most times, and sometime not. In case you have some feedback, do let us know as that is the only way we can improve.