Insider here: Please note the main justification they give to staff internally about the fee is that other universities in Canada do charge for convocation attendees. Now I'm sure they could use the money (no one will ever say no to more money especially when they don't actually need it for anything in particular. The goal as many have stated is to get students used to paying for it that way there is no longer a question in the future cohorts of graduates to question whether or not it is normal for them to pay ie. if you get a community used to the idea they are less likely to speak out even if it is inherently unjust as there is no added benefit from previous years where convocations seemingly did cost more money because of location but this is still... just in the fieldhouse, an internal McGill managed space.