@boots I think that's OK as long as the "salt" is kept secret (so it's not exactly a salt, right?) and unchanged every time that user files a report, but I'd feel more confident using a standard crypto construction such as HMAC. If the salt isn't secret, then it's easy to guess-and-check which username hashed to that UUID. If it is secret, then using the same one across a whole instance should be safe. ...I think.
@boots Maybe you've seen a usage of the term I haven't, I don't know either! In hashed passwords the salt has to be stored in cleartext along with the hash or you can't check the password later. But I'm just nitpicking terminology now, I think.