I'm sure the primary motive of the government is to reduce their spend on social security so the way they are presenting this is disingenuous. However, I'm sure something needs to be done.
Unfortunately the legitimate claimant will certainly be put to more trouble because we have many that just work the system.
We used to employ home-workers to do light electrical assembly. Our people delivered the work and collected it and it paid well over minimum wage (our in-house people could earn well over double minimum wage at the piece-rates we paid). However, we gave up on the scheme because there were so many who, when they found out we wouldn't be complicit in their claiming benefit and working at the same time, just couldn't be bothered to do the job. Sadly lead-swingers are not rare in our society.
Also there is the whole issue of whether your GP is in a good position to do the job? Do they have the time to deal with the inevitable back-chat from those they deny a note? How many of them would feel pressured: fearing possible out-of-hours reprisals from those they refuse a note? My GP is a friend of long-standing - should he be permitted to give me a note if I wanted one? (obviously not!)
A good friend of mine died of cancer recently. She ran her own company and, despite being well over retirement age, she was working right up to within days of her death. A lot of my friends are either self-employed or are directors of their own company and without exception you would have to knock them down with a base-ball bat to keep them from work. Of course, by running their own show they don't have a lot of choice! If we are going to dig ourselves out of the financial mess we are all in we are going to need many more of us to have the 'work-till-I-drop' ethic.
And lets face it you need to be in a hell of a mess not to be able to do anything. If you can sit at a PC and type a message then you are physically capable of doing a whole raft of clerical jobs and I know that banks, for example, farm some of these out to home-workers on the end of a phone/broadband line. The world is crying out for web-page designers - a job you can do from home on a PC.
I just don't buy the 'there are no jobs out there' thing. Although my core business is quite at the moment I'm totally mown-out with work for other sectors - booked solid for 9 months ahead. Also, a couple of friends got made redundant some months ago and by shear persistence they both have good jobs again despite one of them having no paper qualifications at all.