Good question. I initially got told by friends in academia that this is all fine and what they all do if they can't access the paper and they would also hand it over if someone emailed them asking for a copy.
In the end, I guess it depends on who the copyright of the published paper belongs to. If it belongs to the authors, they are free to do as they please, if it belongs to the publisher, you should actually email the publisher and ask for a copy (but good luck with that).
Here are some resources with more thoughts from people in academia and outside on the subject: