I agree, Otto, it is not fair. I have lived with 2 full time students before and as the only working person there the council tax was still reduced by only 25%, despite me being outnumbered by those who were exempt. However, it is also unfair that others eventually pay for those that are defrauding the system. The money lost in benefit fraud means that taxes increase for those who *do* pay them
The council tax benefit logic is, admittedly, questionable. But that's the way it is - at least for now. Instead of encouraging people to defraud the system (and yes, while it IS unlikely you'll get caught, there can be severe consequences is you ARE), it is better to campaign to try and change way the council tax is worked out.