I think this "research" belonged with the rest of the "cutting edge" social science research that is basically a common sense assumption allegedly tested and found to be basically true.
"In a world where you are building walls to keep out bad guys and accept help from everyone without giving it sufficient scrutiny then bad actors could wreak havoc." and "In a volunteer system with no financial incentives there are very likely to be poor systems of oversight and accountability to prevent this."
And yes the students should be placed on probation for a couple of semesters, sentenced to work the freshman computer help desk and ordered to cooperate in identifying the bad code they submitted. (after reading TJ Hooker's other posts it looks like they tried to minimize the negative consequences but failed to make everybody happy and failed to realize that making everyone happy is a key component of a volunteer effort like open source software)