I think cheating is a SERIOUS issue and have no patience or respect for what these students did. HOWEVER, I think it's sloppy teaching to reuse the same midterms and questions over the years. Professors are paid to teach. Them writing their own material should be a part of their job description. They know this stuff inside and out--that's why they're teaching it. Now, I understand their job is busy and difficult in many ways, but I think recycling test material like this shows a disconnect from the professor and his students, and from the professors and the material. At least have some essay questions, or rewrite even 25% of the multiple choice questions would be a great start. Just having the TAs copy and paste is NOT an appropriate way to teach or to write an exam.