Yes, IP addresses are attached to the posts you make on this website. This information is presumably only available to the administrators and whoever they deem fit to view that information. An IP address is not tied to an individual; but rather to the provider that furnishes you with access to the internet. An IP address, for the layman, can provide you with the state and general area. For example, tracing my IP address would lead you to believe that I am in the capital of the state I'm from; however I live and work almost 60 miles from it.
I am certain that Fedex does have the ability to tell who access their intranet and when, but announcing your intention to do so wouldn't really do much to identify you. According to Wikipedia, there are 290,000 employees of the company, any of whom could be accessing that information at any given time. Now, it probably wouldn't be wise to announce that you were going to access a certain obscure file by name/number on a certain date; they can likely see who accessed what on a given day and narrow it down to a few dozen people. From there on out, it would be a matter of reading the posts of the screen name that posted here and correlating their experiences with service records of suspected employees.
That's how I would do it, anyway.