Can users view a calendar in Outlook, but only be able to create/edit events through SharePoint?

I have a SharePoint 2010 calendar that I set up with standardized drop-down fields which auto-populate the hidden title field. This way, our users cannot create titles that do not follow a standard format. However, if a user creates an event through a linked Outlook (we have 2013) calendar, they are able to set any title they like and not use the drop-downs at all. Currently, events made in Outlook appear as a red overlay on the calendar to mark them for revision.

I was wondering if it is possible to allow Outlook linking while denying the ability to create events from Outlook. Users must be able to create them through SharePoint as normal. I would imagine if this were possible that there would be a setting or perhaps a built-in group for Outlook. I have be unsuccessful in finding other posts with this particular requirement, so any advice would be well appreciated.