I understand that it's a non-monetary contribution; my confusion is just on why we should treat them differently from monetary and why people think of them differently, even when they accomplish the same thing (deliver $X worth of value to a campaign), especially given that, for a foreigner to contribute money is a serious crime.
(Less of an issue in your case since you're not some random Chinese government official but an actual US resident with legal status who can stay.)
So for me, the map was a practice exercise, which is essentially like a more convoluted Hello World. The value was perceived by others, and the campaign. The value for me was, "Ok, there's cluttered events all around the wild, I'd like to make sense of it and help out while I practice D3 and Leaflet."
The value as perceived by others was beyond me, and I was really just happy that it had bigger value that I originally intended.
This is different with foreign governments contributing online assets or money to the campaign, because the intent is different, and the worth is different. The intent is influence/leverage, and worth is tools/dollars. And as you have predicated below as well, corporate money is very different if you look deeper, compared to an individual who's just practicing.
http://www.fec.gov/ans/answers_general.shtml#Can_nonUS_citiz...
I personally participated in the 2008 Democratic caucus as a permanent resident. I could take part in the political discussions, but I just couldn't vote (which is a party rule, not a law). I also lobbied state legislators on behalf of the school I was attending.
http://www.fec.gov/ans/answers_general.shtml#Can_nonUS_citiz...
I would, most definitely, not want to create any legal problems to the campaign.
> The Commission has concluded herein that because uncompensated volunteer services are not considered to be a contribution under the Act, any individual, including a foreign national, may volunteer his or her uncompensated services to a candidate without making a contribution to that candidate.
From the PDF linked from here: http://www.fec.gov/pages/brochures/foreign.shtml#Volunteer
Whether the Sanders campaign actually wants foreign volunteers is a different issue.