Maybe only the advanced members that are capable of this ability will be able to use the speed that is unseen by Sharingan.
But, that'll have a condition too: Sharingan with 3 Tomoe (3 black marks around the eye) are able to see the moving player, as Sasuke was able to see Naruto (Kyuubi) moving with amazing speed.
Approved. ^_^
Now create the Jutsus related to it.