this anon has a retired air force frne who was a "chocker"
part of his job was to knock the chocks out from under the jets when ready to roll
so a chocker places and removes obstacles
as an aside he did this is rattlesnake country and they hid under the chocks on the warm tarmac
so they had to bang the chock with another real quick to dislodge then signal the pilot to run over the snake
kek