Similar idea to tony's antipre but without the use of gravity and different delays, jump is disabled for a short amount of time when hitting the trigger due to player_speedmod (there is no real noticable speed change)
Acts like a really delayed auto - holding space in the trigger will jump repeatedly but delayed so ultimately pointless.
- copy the speedmod and trigger, and place triggers like shown
NEW VERSION WHICH IS MORE RELIABLE THANKS TO TONY FOR FINDING SETTINGS
UPDATE: I PUT IN RELIABLE SETTINGS AFTER LIKE 3 YEARS, THIS TIME ITS ACTUALLY USABLE.
NB: doesn't work on 66tick singleplayer, only tested on 100tick (probably works on higher tickrates too).