The students' cooperatives were intended for students (i.e. both high school and academic) to do an odd job - wash windows, load rail cars, clean the novogradnja apartment before handing out the keys, be a stand girls at fairs - and were thus untaxed. This loophole was used in hundred ways, even the students sometimes outsourced their gigs to older guys and kept the margin to themselves. In our case, the local one was the co-founder of DBA.
The inclusion of highschoolers is language incorrect, they are not considered students here, anyone from 1st to 12th grade is a učenik (learner), (see school levels), but for once they didn't go for a complete, long name.