No disagreement, but asking for repeats is, by definition, not Forward Error Correction. FEC is useful for things like broadcast transmissions, where the receivers don't have the ability to send requests for repeats back to the broadcaster. FEC, by itself, can't guarantee that a message will get through. It can be pretty effective at assuring that an errored message won't be mistakenly presented as having been received without error, though. Handshaking can be combined with FEC for more robustness, in those situations where it's possible to ask for repeats.