Two of the "Mad Cobra" coasters, Flight of Fear at Kings Island and Flight of Fear at Kings Dominion, have a mid-course block brake, but Joker's Jinx does not. Where the other coasters have brakes, Joker has these green rings that surround the track.
A blocking brake can stop a train and allow multiple trains on the course at one time, but since Joker's Jinx only has two trains, it is practically impossible to load another train before the first has finished going through the tangle of track. One advantage of the rides that do have mid-course brakes is that they also are used as trim brakes. Trains are almost brought to a complete halt as they pass the brakes, so the second half of the ride occurs much more slowly. Those two rides are rather rough, so going through the last bits slowly is more tolerable than going through at full speed!