In city where I live, shared bicycles have a wheel lock, which is unlocked by a mobile app what starts the rental period and which has to be locked manually by pushing the lever back to locked position to end the rental.
It already happened to me twice that if there was something or someone distracting my attention when I was putting the bike onto its stand and taking my backpack, I forgot to lock the bike and the rental period continued running.
What habit (maybe purely in my mind or maybe even accompanied by a physical token?) can I develop which will effectively and early remind me about the forgotten operation of locking the rental bike at the end of the ride?
(More information about this particular bike sharing.)