Obviously they are aware of your work habits, however, they haven't fired you yet. Be cautious because that the ice may be getting thinner if you continue in your current trend. I would invite you to talk to your sysadmin and ask him how much time he/she spends cleaning up after unauthorized internet use.

And from another grumpy old fart: remember, it's not your computer or your network. If they wanted you to have unrestricted access they would have given it to you.