R exam postprocessing

Following my three-fold R exam of last month, I had a depressing afternoon meeting (with other faculty members) some students who had submitted R codes that were suspiciously close to other submitted R codes… In other words, it looked very  likely they had cheated. (A long-term issue with my R course, alas!) During this meeting, they actually admitted either to directly copying on their neighbour’s screen, due to the limited number of terminals that forces students to be too close to one another, or to looking at (and copying) another student’s  R code file from an earlier exam.  I used different exams but with enough of the same spirit that some of the R code could be recycled.) Besides the pain of having to turn to disciplinary action at a level where students should see the point of getting real skills towards an incoming hiring, the depressing consequence of this state of affairs is that next we will have to move to a higher level of “security” when running the R exam, which most likely means we will turn back to a pencil-and-paper exam…. A paradoxical situation when teaching a computer programming course! But unless some unlikely sponsor delivers a computer room able to handle 180 students all at once, I do not see any other solution. Suggestions?!