[quote=@RyuShura]
Citizens of the mega-city are mandated to possess a 'Identity Trace', an implant that allows the Apothos system to suppress a defective gene in humanity, known as 'Sin' 
[/quote]

What I took from this is that the implants act as a convenient method for suppressing this gene by administering this Serum upon death as soon as vital signs cease to function.

I could be wrong, but if it doesn't then it would be quite the inefficient system as inevitably some bodies would fall through the cracks/be unobtainable as you pointed out. Hell, some people in the real world die in their homes and don't get discovered for years (Admittedly, not a super common thing) In a large city as this there's no way there would be enough manpower to physically go to every deceased and administer this serum. 

I suppose if the implant alerted proper authorities to death when it happened, it could be more plausible, but with a city as large as this, it likely has a fairly high death rate.

Which would also be why tampering with it would be highly illegal.

I could be completely wrong though, just my thoughts on how it would work in a more perfect system. Probably shouldn't do that considering the genre of this RP, but eh xD

Best probably to wait for Shura to clarify entirely.