Locking of a filter allows you to lock down the data selected so that anyone else who has View Only access to this report will not be able to change the locked filters. This will allow you to give very restrictive permissions and have better control over the access your users have.
Additionally, you can always 'Lock' the filters on the reports. The schedules are not synced with the report template by design so that you can have multiple schedules per report template but you can force them to sync by "locking" the report filter.
By following the steps below you can easily lock filters on your reports.
Step 1: Drop into the filter on the report that you want to lock down and set the selection as it should be and choose the green checkmark:
Step 2: Select the lock icon next to the filter that you are wanting to lock to your report.
Step 3: Select Save As to save your report with a name of your choice.