I wouldn't do any of that because it doesn't address the basic problem of users writing bad code for their reports. Instead, find the users that are writing the code and show them what's going on and how to kill their own runs. If you help them with tuning their code a bit, the problem will go away.

The real problem, of course, is the original sin of letting users write their own code. For a week, let the runs finish, collect the data, and submit a proposal to disallow it in the future. If management refuses, then just let them run until they get the idea. 😉