Can I make the Calendar completely read-only.
Obviously you can do this with access privileges so that users can't edit the events table if they log in with a generic account (or open the file without logging in). While that locks down your data, that change won't be reflected in DayBack's interface: users will still be able to begin creating and editing events, those actions just won't complete.
We should be releasing an in-app update after DevCon that lets you reflect read-only access in the interface (disabling drag, hiding the delete buttons etc.)
Read-only calendars were introduced via an in-app update in version 9.71: now your startup script can set any given calendar source as read-only, meaning that you can do this conditionally based on the logged in user.
Can individual events be made read only?
DayBack will respect any record-level-access restrictions you put in place in your FileMaker tables, and these can make some records read only (for certain users) while leaving others editable. However, this read-only status won't be reflected in the calendar's interface. So a user would be able to start dragging and event to a new day, for example, only to see a dialog come up letting them know they don't have rights to edit the event. In summary, record-level-access can be used to prevent users from editing some events, but those events will still look like they are editable until the user tries to save their changes.
Sharing read-only calendars
You can also share your calendar (or a filtered subset of your calendar) online with folks who don't have access to your FileMaker solution. More details here: sharing.