I've been destroying my old palisade using wrecking balls. Some pieces had cave in boulders stuck in them.
The first time I noticed this was when I placed the WB on one of those tiles: it destroyed the palisade, caused no cascade. It then let me do Wreck again to destroy the boulder with the WB. This happened already twice.
The second time, I tried destroying a "clean" piece of palisade. The cascading effect stopped right before the tile with the boulder stuck in it.
The third time, I tried destroying a "clean" tile between 2 tiles with boulders. It only broke that one tile, with no cascading at all.
I know cascading is random, and this might be a coincidence. But so far all tiles with a boulder stuck in it have stopped cascading 100% of the times. Given the 24h timer on WB, and the security issues linked with leaving stuff open, I can't keep testing. Might be worth looking into it.