Show up with a child: clearly you can look after a child some of the time, extrapolate to 100% of the time --> you can work.
Show up with clean clothes: clearly you can look after yourself and get somewhere on time occasionally, extrapolate to 100% of the time --> you can get anywhere and talk to anyone, no health issues, you can work.
Show up alone or walking without aid --> etc.

The whole procedure is a distraction, just like the deficit.

Real goal: "We will spend less on disabled people."
Official statement: "We need to help those who can work get back to work."
Distraction: "This test will tell us something or other."
Result: Morons spend time criticising the tests.

Real goal: "We will shrink the state and lower taxes, mainly for the rich."
Official statement: "We need to save."
Distraction: "Deficit. Deficit. Exterminate the de-fi-cit."
Result: Morons spend time criticising the specific savings.

So angry. Apathetic. Where Sue Marsh and others get their energy to carry on I don't know. Maybe I'm not angry enough.

(Disclaimer: Not personally disabled or receiving any of these benefits. Have a job making above median salary. As Pratchett said: "indoor work with no heavy lifting".)