Then you would probably try to piece together your tax liability through indirect methods, completely analogous to what they did here to recover the emails. What did you expect they'd do?

Say, if you claimed $1000 in charitable donations but lost the receipts and got audited, you'd probably be able to go to the organization you donated to get their records. If they couldn't produce them, you'd probably have the deduction disallowed and have to pay back taxes + interest.

If you're going to try to glibly score points, chose a better example.