Agreed.When I did my Portable Appliance Testing course last year, I asked about brand new appliances. Short answer was that , you should trust the manufacturer. But...... probably needs to be tested to cover your own back.
However...
... is complete bobbins.Just remember, with IT equipment, you should only test the mains cables, not the IT equipment itself.
If you have a PAT instrument capable of performing 'soft' tests for IT kit, then there is no reason why the appliance shouldn't be tested, rather than just the supply cord.
If, on the other hand, you are unaware of what these soft tests are, or don't know if your tester can do them or not, you shouldn't be doing the testing in the first place. Or should have paid more attention to the training course, and the IEE CoP!