It is easy to be opened by technology, the end of the marble is exposed and the working stroke is short. The marble can be directly touched by foreign objects (wire hook, tin foil, etc.). The opening rate is high. Non-locking keys can enter the lock cylinder, which is easy to cause the keys to open and The keys are not open to each other; the keys can be locked into other people's homes, and some can even open other people's locks. A key can open several locks, and the keys are easily copied.
To sum up, the principle of the marble lock is known to many people. If someone with a heart wants to unlock, it is simply impossible to prevent. One of the most common A-class locks can even be opened in a matter of seconds, faster than using a key. In film and television dramas, we can often see that some masters use a wire, etc., and slam into the key, the lock can be opened.