Allow cancelevent to work with ~onPickup trigger

Dagger:
  Id: IRON_SWORD
  Data: 0
  Display: '&3Dagger'
  Lore:
  - '&6A powerful dagger'
  Skills:
  - cancelevent{sync=true} ~onPickup

This is the boiled down skill. I am trying to prevent certain players picking up the item via conditions. But this does not seem to work. It would be nice to cancelevent if this is not a thing already.