[ninalanyon]

It was the same when I studied applied physics in England many years ago. No one checked or cared if we attended lectures in the physics and maths departments. In fact anyone could have attended the lectures even if they were not a student because there was always plenty of room. But the law department where my wife studied, at the same university, did check who was attending.

As for laboratory exercises in the physics department, they were in theory compulsory but still no one checked. The final year included a long experimental project that had to be documented and conclusions defended in a viva. Again no one formally checked that we actually did it but as we were grouped into small teams for this anyone who didn't pull their weight would have been reported by their fellow students and would not have had access to the experimental results which would have made it difficult to write it up and defend.