Since I'm one of those 'geeks' (actually a network analyst in a large health authority) and there doesn't seem to be a great respect for my type here, I'll keep this short.
If you absolutely KNOW it's a (non-powered) hub and you know the difference, you're probably just fine. However, if any of those wires is connected to a switch or router, especially one that provides PoE (power over ethernet), you could cause all kinds of trouble. We get automated alerts every time someone does something that "shouldn't be a problem" with our network....
BTW, check out the replacement prices for a new Cisco PoE switch sometime. If that doesn't make you careful, nothing will!
