A useful tip that taught me my friend Roland Jean, Demis Roussos Pianist/Keyboards :
The rigid rubber band under the pedal to prevent it slipping.
I always had this problem with my pedals that slipped under the keyboard. If I forgot to “gaff”, they retreated backwards. Sometimes I had to slip under my stand to return them to their places.
The principle of this trick is the same as the sustain pedal on the Wurlitzer with its long metal strip to the front which is under your foot. The heel blocks the band and prevents the pedal to move forward with each press. The principle is simple, “mechanical” and above immediate even on slippery ground such as tile.
I bought a single rigid rubber band of 40 cm in a hardware store that I stuck below the sustain pedal. It can also be screwed but think of sticking a felt on the screw head to avoid scratching the floor.
You will not need to gaffer tape or lose money on ineffective anti-slip.