Hey @hellowebsites,
Just to be clear, in your post here do you mean “conditional logic” instead of “conditional login“? I only ask because login functionality and different admin/permissions-related things change the scope of this issue a lot.
But if all you mean is conditional logic to use in your templates, then yes, there are several options for marking an event as “canceled”. There isn’t an “official” way to do it in the admin, like you asked, but there are many options of the “iffy workaround” variety that you mentioned – one of the simplest ways would be using a custom field to mark events as canceled. You can learn about custom fields, and how to check for them in your theme, here → http://codex.wordpress.org/Custom_Fields . You should be able to use custom meta like that to not have to actually delete events, but write custom code to filter them out of whatever public-facing views and templates you’d like. Let me know if this helps at all or if you have any follow-up questions here!
Thanks,
George