Hi wow,
You’re definitely not the only person interested in this kind of functionality. Depending on what you want to achieve, there are a couple ways to do this using custom code or a user manager plugin. I recommend that you read over these other forum threads for some ideas:
Make a specific Calendar catagory private
Access Control / Private calenders
Make entire calendar private?
As mentioned in one of the above posts, any custom code or additional plugins that could help you with this will work in either the free or premium version of The Events Calendar. So you can test it out with no purchase necessary and figure out if it can do what you’re looking for.
Thanks for asking, and don’t hesitate to let me know if you have any followup questions.
Cheers,
Leah