They do, but there are also RFID tags that contain a microcontroller that can power external components from RF power, so potentially you could embed up with on

They do, but there are also RFID tags that contain a microcontroller that can power external components from RF power, so potentially you could embed up with one that has an external flash chip (probably wouldn't have enough power do do a write, but maybe could still read it) Edited to add: for example, the LPC8N04