> [...] conflict avoidance - a reader can detect when it's reading more than 1 FeliCa card at a time, and prevent any reading if so [...] That must be one of t

> [...] conflict avoidance - a reader can detect when it's reading more than 1 FeliCa card at a time, and prevent any reading if so [...] That must be one of the things that ISO 14443 has improved on then, compared to FeliCa: At least 14443-A (and I believe also B) allows addressing each card in the field individually by its serial number, and then selectively "halt" or resume it. Practically, this means that the reader can talk to cards one by one until it finds the one it's interested in (if any). Unfortunately I don't know any practical system making use of that (it could get pretty confusing with payment cards, for example – charging a random card of several possible ones sounds like an anti-feature), but I still find it very neat.