Say I have this setup of 1x1s, and I'd hit the 3rd row with this wand, replacing it with a 1x16
1111111111111111
1111111111111111
1111111111111111
1111111111111111
Once those bold bricks have disappeared, the bricks on the 4th row have no more support. Blockland automatically deletes floating bricks(except of those that are loaded). So, once the 3rd row is deleted, no matter how fast it's replaced by a 1x16, the 4th row will collapse.