It would be pretty easy to verify if these were truly art students selling artwork. Find out what company they're working for and contact that company. Since no one seems to know who these students worked for, I have to assume they were here for nefarious purposes.
Over the years, we've had people going door-to-door in our neighborhood. Many of them use bogus "college student" claims. One said he was a scholarship soccer player at UGA when, in fact, UGA doesn't have a soccer team.
I paid green cash. Got some kind of receipt from him but I don't remember where it is. I didn't do it as any show of support for anything; I did it because he had two paintings I thought would look good in our home. Maybe I will indeed shoot some digipix of them and show them to Freepers here. :-)
MM