So at $8000 / month that's a minimum of $96,000 per year. If we assume the cost overruns are on the same order as the wonderfully advanced automated parking system then its safe to double that number to $200,000 per year.
With a maximum of 4000 students in residence this means an the cost is likely an extra $50 per student in residence. The current lock out fee schedule is:
http://housing.mcmaster.ca/Building_Services/keys.html
Your first lock out key is free of charge.
Lock out 2 & 3 = $3
Lock out 4 & 5 = $5
Lock out 6 & 7 = $10
Lock out 8 & 9 = $15
Lock out 10 & following = $20
So if you plan on locking yourself out more than 9 times per year you may be saving money, otherwise why change a system that appears to work fine ? Its not like this system eliminates keys, you still need a key for your door. You can also bet that there will be problems implementing the system despite what the vendor claims (again see the parking gate fiasco).
If Housing and Conference services has extra money lying around, perhaps they could use it to reduce residence rates, contribute to bursaries or increase the meager pay of CAs rather than buying minimally useful but very expensive tech toys.