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Hi Adam, Are the ticket pages on the sub domain the same as the event pages on the main domain except with the ticketing system included? If yes it would make more sense to canonical each event ticketing page back to the same event page so: tickets.domain.com/event1 -> domain.com/event1. If the ticketing pages are not meant to be indexed at all then I would put the robots no index tag on them also (or a robots file on the whole subdomain) and keep an eye on GWT to make sure none of them creep in. Canonical tags are a 'recommendation' not a rule so if your plans are for these pages to not be indexed at all best to ensure that as completely as possible.

As far as I understand this, to your browser and to Google, they're the same page (this really seems to only apply to the homepage, other pages "/" really matters a lot). I would not worry about changing the canonical, in fact it's technically the 'right" location of the page. When it comes to the HTTP docs, a request to the root needs "/". All modern web browsers add it back in for you even if it's not there. This is I believe why the canonical is set as it is there in yoast. I covered this in a blog as someone asked this at Pubcon this year in a keynote. http://www.winstondigitalmarketing.com/yoast-homepage-canonical-correct-include-trailing-slash/