You need to contact the Moderator via PM who banned you, which I suspect was RobbieJo as I was there when you said you were using it. It also means you never read the EMC Rules when you joined: 3. Thou Shalt Not Cheat Don’t use any mods or game exploits that give an advantage over other players. This includes see-through texture packs, modifications that allow you to move, jump or fly in a way not intended by the default game settings, and any game glitch or exploit that gives you an unfair advantage of any kind over other players. If you are caught cheating you will be permanently banned. If you are unsure whether a certain mod or other activity is allowed ask a moderator. The Forum isn't the right place to appeal a ban.
It's a Mod that lets you move in a variety of ways such as running faster, jumping higher, etc. http://empireminecraft.com/threads/mod-request-smart-movement-mod.7529/
Wud it just look like you were using flying mods or something to people who dont have smart moving mod