HI,
If technically that is the best solution for your needs then a couple of things to keep in mind:
1. If you are using Universal Analytics subdomain tracking is included by default so if you put the same analytics code on your subdomain pages then you should not be seeing any 'bounces' - google should be able to figure this out also.
2. You can install GWT for the subdomain also. I dont think you can set the preferred domain for a subdomain setup but you can use GWT to monitor issues and make sure that duplicate pages for the subdomain are not getting indexed.
3. To avoid indexing of the subdomain pages (which I assume you don't want) you could canonical them to their equivalent on the www domain. You could also meta robots no-index them all. If they creep in anyway you can use GWT to remove them.
If the subdomain is a complete clone and the experience is seamless then why not make all links on the subdomain go back to the www domain pages. That way the only pages available on the subdomain would be the ticketing pages and the rest would be on the www as normal.
Hope it helps.