kathryn
Cathlete
They kind of scare me - the feeling that they could slide right out from under me and I could hit the floor.
They really aren't that hazardous. You always have the heel (or toe, depending on the move) off the disc, ready to 'apply the brakes' if needed. The whole foot doesn't go on the disc.
(A safety suggestion for those using frisbees: make them more "Gliding Disc" like by trimming down one of the edges, enough that you can have your heel off the disc while the rest of the foot is on it and the disc is flat).