Welfare is only fair if everybody gets it equally, not just the needy, and pays for food, and on top of it you can have a job, and buy like a fancier place than provided by welfare, or fancier food.
'No it's not fair, it's a matter of policy. Capitalism is "fair" -- you get money for doing others favours, and can buy favours in return. Any kind of tax or welfare disrupts this and is inherently unfair in this view. Most people don't, however, agree with the capitalistic definition of "favours" (or what ever the economists call it), or that you can accumulate or transfer unlimited amounts of such. Tax can then be seen as a fair way to dampen the dependence on the history of the system, placing more emphasis on recent favours. The rate of the tax and how it is spent is more of an ethical issue than an economic one.
The world is not fair, so a system that's internally consistent and fair, but doesn't take into account the different "luck" people have, probably doesn't agree with most people's concept of fairness.
All that said, I agree with the idea of giving everyone a basic wage (called citizen wage in my country, can't remember the English term). The productivity would probably drop as people did more useless things or did nothing, but we may also see more amazing breakthroughs, as the risk to any peson is lower. (currently, going on welfare and developing a new kind of nuclear reactor is seen as quite unaccceptable, yet there may be smart people who can't make it in academia or industry, and now have to take crappy jobs) This policy will become a necessity to have any kind of fair and humane society once automation makes even more jobs redundant, and we can only hope that people will accept the potential loss of productivity before it's too late.