Do not worry too much, it never said not at all and if reporters starts getting paid one needs to be worried 
It also says "one accurate report is worth many inaccurate reports" which could be interpreted that being below 70% shoulnd't be a problem at all. There's no better way to deincetivize (already low) reporting than including the high percentage as one of the requirements for a badge as people will rather not report it than risk lowering their percentage.