Question For Mods About Being Banned And Upgrading

For the first time in a long, long time I was banned from my work computer today for no apparent reason. I did a little research and discovered that all 5,000 employees at my site have the same ip address. I'm guessing that one other employee did something inappopriate and got me banned. My question is this..if I were to upgrade, how would you be able to tell if it were me making inappropriate comments or one of the other 5,000? More importantly, if I upgrade, does that mean that everybody at my worksite gets free reign on my dime?