Because RFID is a family of technologies operating at 4 different frequency bands and using 2 different coupling mechanisms, it is difficult to generalize. For

Because RFID is a family of technologies operating at 4 different frequency bands and using 2 different coupling mechanisms, it is difficult to generalize. For the use case of ID cards, 13.56MHz and inductive coupling are the relevant characteristics. Anti-collision is pretty weak in most 13.56MHz transponders, and it is no better than it was 8 years ago.