…which is to say I don’t.
In the realm of contemporary touch-free interface, RFID and NFC are probably 95% of the pie. They are widely adopted in building access control, contactless payments, mobile-to-mobile sharing, supply chain management, and even hospital patient tracking. For these purposes they are remarkably inexpensive to install and maintain, and the technology is mature. Given these benefits, it is not unreasonable that one should want the convenience of contactless access control without the key fob, chip, or smartphone, and so a small community of DIY RFID-implanters has come into existence.
The notion of implanting an RFID tag is not wholly unreasonable (no so different than many other types of mainstream (implants) and alternative (piercings, tattoos, etc.) invasive body modifications). After all, my two dogs have painlessly carried an RFID chip in the skin between their shoulder blades for years now (for non-pet owners: this is a common practice to allow identification of lost pets). Such purpose-build tags are biologically inert and as RFID does not require a local power source, they do not contain any harmful chemicals and do not radiate unless scanned — they are just a little glass, plastic, metal,