Difference between "Return" and "Warp"?

[StouterTaru]

This is what the bots and rmt use I'm pretty sure. You know you've all seen it before. You see the BLM Bots standing around then they instantly teleport with no cast time? This is most likely the exploit they were using.

No, they just tell the server they are somewhere else, and the server says OK. Movements are handled client side.