That's very interesting. I just called their endpoint: curl -d '{"onlineId":"zeta0134","reserveIfAvailable":true}' \ -X POST https://accounts.api.play

That's very interesting. I just called their endpoint: curl -d '{"onlineId":"zeta0134","reserveIfAvailable":true}' \ -X POST https://accounts.api.playstation.com/api/v1/accounts/onlineIds \ -H "Content-Type: application/json" And got a response indicating that the name was both valid (i.e. not "improper") and available. Maybe at one particular time the word was flagged, but I can't imagine why. edit: As other repliers have said, I did think that it could have something to do with Los Zetas, and maybe that was the case in the past. However, as of now, `zeta0134`, `zetas0134`, and `loszetas0134` are all valid and available names, according to the endpoint. Interestingly, `pabloescobar0134` is considered improper. However, `elchapo0134` is not – which supports the argument that Sony's blacklist is (obviously) manually curated and perhaps subject to change. Maybe enough people who wanted "Zeta" complained for Sony to realize it was a word that had many more uses than in Los Zetas