If that were the case (that you'd be unhappy if someone installed something on your box without your permission), then something is wrong with your trust of privileged users or your system setup. If anyone other than you can physically go in and install programs system-wide, then that's because you trust them enough to do so without your express permission. Or like I said, your box security is not setup as well as it should be. I'm just speaking in general, this doesn't overly apply to the OP.

NB: I'm not saying that it's alright to do whatever you want on a system because your sysadmin gives you additional privileges, but that if your sysadmin gives you the privileges to do something that you will use the extra resources appropriately and responsibly.