You don't have to come to uni to accept your offer.
Anyone can accept your offer; in fact, we're even accepting acceptances whor'e signed by anyone who's carrying the acceptance paperwork. It's not a binding contract of any sorts; it's just an indicator of interest allowing the uni to coordinate enrolment better for everyone.
If you would prefer to send it in, you can send it to;
Undergraduate Studies Section
Macquarie University
North Ryde, NSW, 2109
You need to enclose your acceptance slip (or something with all the details: your name and UAC Id number, the course you're interested in, the UAC course code and address), and write your address somewhere so that we can send you an information packet, with all the details you need between now and enrolment.
Please read all of the information pack to make your (and everyone elses') enrolment less painful.
But:
You DO have to come to uni -- IN PERSON -- to enrol.
...unless you get a power of attorney to allow someone else to do this -- there are HECs/other paperwork that you are required to fill out. If you need to get around this, go see a solicitor and get a power of attorney for someone to do it for you. There is an unadvertised late enrolment day for all of those people who won't be here on the day, but that incurs a $200 late fee, and you must write to Anthony Tse to ask for permission to come to this.
Call the undergraduate studies section for more info -- you might even talk to me (Steve)!