One of my roller-powered lead minecart grinders jammed because I threw about 60 greater badgermen on horses in at once. I now had 100-odd bruised and angry badgermen and horses stuck under my entrance bridge, with no safe way to let them out. Magma was considered and discarded, as I didn't want to go to the trouble of rebuilding everything after it all melts. So, I built an extension to my pump stack to turn the grinder pit into a drowning chamber. Only a few minor flooding problems, quickly contained, occur as I build a drainage system, and the test run successfully provides me with another few years' worth of horse meat and badgerite.
Fast forward a few years. I've replaced the rock-filled lead minecarts with lead-filled gold minecarts in an attempt to increase lethality and reduce jamming, and another 60+ mounted badgermen lay siege to my fortress. I drop them in as before, flip the switch to begin harvesting this year's crop, and go back to supervising my military as they hunt down a forgotten beast in the third cavern. After a while, I notice the siege still hasn't broken, so I take a look in the pit. All of the minecarts are piled in a line ending in a corner, once again there's 50 angry badgers and their horses in my pit. I take a closer look, and find, in the corner, "dead muddy cave wheat" instead of "Obsidian Track NE".
Looks like I'm going to have to rebuild everything anyway to make it plant-proof.