So now you have two workloads, and they have half a workload, and there are differing standards to which you and they are held?

I admit that I come at this question from a very bitter place. I have been woken up many, many, many times at 3 AM to deal with a problem that someone else caused, out of sheer laziness or incompetence. Those people suffered no consequences. Had I applied the same level of due care to my own duties in fixing the problem, however, the consequences would have been different, and significant. It is difficult, in such circumstances, not to stew over things a bit.