This is an economics problem and this teacher should work with their Econ department to change the rules for course auditing and increase reputational costs to disincentive this behavior. A few options: 1) Make auditing those classes more expensive by limiting the total number of courses a student can audit, or capping the number of students that can audit those courses. 2) Make auditing a remote-only class option. 3…
Assign the students a project to filter out students with ulterior motives from a theoretical class. The engineers will then be forced to produce a solution for the problem of their own creation while subtly alerting other students that not everyone enrolled in the course is there for the same reason.