Restricting access to certain rows

edited 12/09/19 in Smartsheet Basics

I have a smartsheet for travel requests within an organisation of about 2000 people. Each row contains the requester's e-mail and details about date, destination cost and purpose of travel. I then use formulae to display remaining budget, etc. to approvers. Within the organisation there are about 15 people who can approve. I have shared the sheet with these 15 people. The full 2000 do not have access to the sheet, but instead enter their requests via a form.

I am trying to find a way of giving each requester the ability to see their own requests, but no-one else's requests.

I thought I could do it by giving everyone access to a report which keys on current user, then give all 2000 people access to that report. However, if they do not have access to the underlying sheet then no data is displayed.

I then thought of giving everyone access to the sheet and using a filter on current user. However, its easy for anyone to disable the filter.

Can anyone suggest a way of achieving what I am looking for?