I hope the <call> command never reaches FFXIV. It was brutally annoying because people abused the shit out of it and it ignored system volume. AKA: Your sound is set to low and someone in PT does a <call> and it blasts at full volume, waking others in your home.

You also need to consider that if it was implemented, they couldn't add a toggle for it, because that would defeat the purpose. The game is better off without <call>. Best just to assume that if someone is AFK, they have a good reason, and they will come back when they're ready to do so. Life > Game.