Putting a flag in the sand

There was a discussion about a technical issue on a conference call. Two people had different views, and one was so determined about his position that he uttered this malaphor. It appears he was trying to say “put a stake in the ground” (making a firm decision or determination) but instead he mixed “line in the sand” (a figurative boundary where no further compromise can be made) and “plant a flag” (making a firm decision). A hat tip to Mike Kovacs for hearing this one.