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This is the only undetectable membean userscript that I have seen. How the other "cheats" work is they click a hidden button that the membean devs purposefully put there to catch cheaters! This script is undetectable because it works by clearing the cookie that remembers when a question is answered incorrectly. What this script essentially does is deletes a cookie, which is something that any user can do manually, so it would not be possible for membean to detect this in it's current state.
Doesn't work. It just says that it's active and reloads the same question until the system marks it as wrong.