There's three issues that come with using your method.
1. Does that software connect to proxies in which the owner authorises such connections? If not then chances are the user of the software is breaking the law and if you connect to a server in a given country you are subject to the laws of that country as well as your own.
2. The university in question obviously prohibits on-line chat in any form, otherwise they would not single out the IRC ports when choosing what to block. If someone gets around this in some way, such as the one you suggest, then they are liable to expulsion from the institution if and when caught.
3. IRC networks look dimly at connections from proxies. Insecure proxies can be dealt with easily because the software can quickly discover it. Some networks ban the use of all proxies unless you are either the owner or authorised by the owner to use it.
So at the very least the user can look forward to being banned, notwithstanding the fact that the user is connected to what could be an untrustworthy machine, therefore is also a security risk. If you are just repeating what you said originally then your post was rightly removed.
