I like my Xiaomi M365 so much that I don't want it to be stolen. There are some anti-theft devices around but most just block a wheel. Besides not protecting the scooter from beeing carried away or moved on the other wheel, I don't like the necessity to bend down when applying those devices.
This is why I made this thing. Basically it is a 1 m long stainless steel wire with a lock and the parts to store this on the scooter when not in use. The 3 mm diameter wire is secured by pressed aluminum ferrules.
Two separate parts - each split into two halves - have to be mounted on the steering rod of the scooter. The upper part holds the wire and the lock in place and the lower part offers a hook around which the wire is wound when not in use. As each of those parts is split in halve, they can be easily attached to the scooter by tightening those halves together using M3 screws and nuts.
For prolonged outdoor usage the parts should be printed with ABS.