According to the ICONstitution, these are duties of a P-Rep:
They’re discussed in more detail on page 14.
If the ICONstitution applies both to Main and Sub P-Reps, then Sub P-Reps not running a node are avoiding their duties. I suppose in that case they should be warned and requested to fix the situation either by setting up the node or deregistering if they do not plan to contribute. If none of those actions within a reasonable time frame would be taken, disqualification vote could take a place.
What do you think?