With regards to the logic on batch jobs.
If a batch does not get cancellation logic, if there is no response time over a certain period that the cancellation logic is applied i.e. no response for 5mins the job triggers cancellation logic and cancels the job.

We have had a case where a email distribution batch job never got a response or received cancellation logic so it was never able to be stopped until we had to force cancel the batch job, I would rather have a job time out after a period of time rather than force cancelling the job.