Trapville is a middletech to hightech world-city (World of Progress/MPA affiliated). It is a free-breeder world, with a wildly different method of population control to others faced with this problem.
Each and any public space may be trapped. The humans populating the world develop traps as their 'civic duty', everything from deadfalls to pit traps to mechanical projectiles to... you name it. The limitations are that it may be triggered by any non-sentient method desired (expert systems on up are considered 'sentient'), it must use mechanical force to cause damage, and it must be at least reasonably possible that the trap could cause casualties.
There are 'trapbots' which wander at random emplacing and replacing and altering traps throughout these public spaces. And, just to keep things interesting, any area connecting directly to a food service or waste service area is considered to be 'public'. And of course, for public health reasons, food service and waste service areas may not be located immediately adjacent to each other.
The public transport system is free, but it is public. There is a 'tax' of a minimum of one acceptable trap per month, complete with AI support in the designing of the trap - all you need is the creativity, the AI handles the physics, mechanics, and/or electronics required. No human may emplace a trap, nor may they specify an exact location, but they may limit the trap to certain terrain features or the like - "Only in dark corridors" for a tripwire onto spikes, for instance.
It is unproven but widely suspected by most inhabitants that the whole planet is under microbot surveillance by the AI which conceptualized and built Trapworld. The AI's name is unknown, but is rumored to be an ascended Rube Goldbergbot. The surveillance is unavailable to outsiders, but portions are caught by 'lucky photographers' and makes one of the most-watched 3D programs on the planet.
Text by John B
Initially published on 12 May 2002.