The Autolock feature allows you to guarantee that no one is allowed to add or modify a timesheet entry after a certain period. However, allowing users to change their timezone presents a loophole. Let's take an example. Piku lives in New Delhi, India. You have enabled "weekly autolock," and now.
Piku shouldn't be able to add any time entry past Sunday.
However, on Monday morning, Piku realizes he hasn't made timesheet entries for the last week. He can change his timezone to USA/Eastern and now NeetoInvoice would allow Pike to make the timesheet entry since it's still Sunday in USA/Eastern.
This is why some admins do not allow their team members to change their time zones.