still possible to detect pretty easy...
calculate how fast you can be without using cheats, what's a possible speed of character, how many sqm he can run under a few seconds...
if a character would pass the amount of possible tiles a mentioned times, he would be detected as a dasher and actions could be taken from that point, whatever the owner would decide, delete, ban, freeze or something
Edit:
Making an easy calculator.
Base_ground = slowest possible tile
stone_floor = 100 (maybe)
calculate level and speed items that the char is wearing, set a time to pass like 20 tiles, use the variables from base_ground to decide how fast it can move on certain floors.
add 1-2 extra sqms to give more exact detections, and no misstake detection on fair players.
and there, you got a detection for it.
However you will have to either have something to determine the speed of floors, or set them yourself.