[tmh88j]

>Perhaps your system goes down and you need it fixed ASAP

So you're saying, all this person is hypothetically doing is sitting around waiting for something to break, presumably at night? You don't think the company would delegate other tasks as well?

>Likewise with mentoring/helping other staff, sometimes this is just far easier to do when you are physically present.

That's not benefiting the company in any way? How is that just "your time"

[jiggy2011]

My point is that it is often beneficial to the company to know that you will definitely be available during certain hours.

Obviously you are going to be doing other work during these hours assuming that there is something to do.