Should we have a welfare system or safety net for disabled and poor?

Society should always have safety nets for disabled folks and and the poor. There is already a means test (at lease in the US) in place for people on public assistants. To test them in the manner you suggest would be costly and I would think not really rule that many people out. Some states in the US are starting to drug test people to see if they are abusing the system. This is a fabulous idea but again it will be costly.