OCP's reasons for waiting until the 17th/18th are ridiculous.
1. "We start contacting those employers to see if they can add an interview room or otherwise accommodate all the students interested in interviewing with them. We don’t eliminate all oversubscribed schedules, of course, but every additional interview makes our efforts worthwhile."
So, they can't tell us which interviews we landed because other interview slots might become available? This is silly. All they have to do is give us our schedules, create "waiting lists" for firms that are oversubscribed, and then send us emails adding those interviews if the firm decides to add more slots. Other schools do it this way. In addition, if they released schedules earlier they could allow us to select open slots with firms that were undersubscribed.
2. "In addition, the Symplicity scheduler does an excellent job, but no scheduler is perfect and so we must check each and every interview schedule to make sure that it has slotted students correctly."
This would require, what, a day?
3. "Finally, several students, particularly rising 3Ls, start canceling their interviews at the beginning of August, as they receive offers from their 2L summer employer. These cancellations create further interview slots which we add to your interview schedules."
Once again, simple waiting lists would solve this problem.
The downsides to such a late schedule release (less time to prepare for interviews, less time to mass mail) far outweigh any benefits accrued by keeping it all secret until 5 days before interviews begin. We should all write to OCP asking them to rethink their strategy.