Look, I hate M$ ass much as the next guy. (Although, if the world were run on Mac's and LInuz boxes I'd probably be installing drywall right now...)
But as a real-life sysadmin, I really get perturbed at this concept businesses and schools and other institutions that own computer hardware and provide it to users for educational / work related purposes are Nazi's if they insist that you keep you hacker mitts out of their systems.
Admittedly, most don't, but when I oversee the design a computer workstation image, I make sure that every nook and cranny of that image is tested. If there are problems, they get fixed. My users don't experience blue screens and phantom lock ups. Before we invested in the technology that sends a notice when new applications are installed, my help desk calls for software problems were 99% related to some jackass that wanted to install WordPerfect 6.1 or burned X-Agent gaming onto a CD and tried to install it. The users that had lockups were ALWAYS related to some downloaded or imported application.
HELLO, PEOPLE! The computer you are using doesn't belong to you, it belongs to your employer/school and is provided as a tool, not a playground or vir0tual break room. The reason they don't want you installing shit on their machines is that there is a CO$T associated with every bit of network traffic, every byte of disk space, and every cycle of processing power. Not the least cost of which is the salary YOU are getting paid to download Virtual Warrior or the Sexy Playmates screensaver.
If you want a computer at school or work you can do whatever you want with, buy a laptop. If your network isn't accessible to laptops, get a cellular modem. You don't just have an unlimited right to do whatever you want with every computer you touch just because you know how to.
Please, if you loaned a friend a car and he brought it back to you having put a low-rider package on it with hydraulic shocks and neon running lights, would you be pleased? If your neighbor came over to use your computer and fdisk-ed you hard drive installed Windows 95 'cause he didn't know how to use Linux, how happy would you be?
Unfortunately, installing one lousy application can really screw things up on a system. That's the function of a poorly design OS; you never know what application won't work correctly once you've installed the Yahoo! toolbar or allowed that PayWare application to install BonzaiBuddy.
My images ALWAYS include TWO browsers (IE and another, usually Firefox or Mozilla), two Media Players (WMP and Real, maybe WINAMP), and EVERY application you might conceivably need to do your job.
If you need an application to get the job done, to finish a paper, or complete the days work, your system should be designed to allow for the testing and integration of that product. Rather that trying to figure out a way to fly 'under the radar', DO YOUR FUCKING JOB. If you need additional software, go through the proper channels to get it.
And remember, even if YOU can be trusted, if YOU are sure that the application YOU want will be OK, or you don't need them to support you at all, what about that moron in the cube next to yours? If you were supposed to be able to install whatever you want, you'd be in the IT Department wouldn't you?