Him wearing Uchiha garb and Sharingan has nothing to do with him being able to escape from Sasuke after attacking him. Attacking enemy is involved in both cases.So both would attempt to attack or capture Shin, Irrespective of Shins intentions i.e. regadless of whether he tries to fight back or run away. When Shin went to fight Sasuke(Obviously, he need to fight him to know how strong he is), his father didn't said anything like 'Stop it Shin don't try to to fight him. he's out of your league.' But he did attempted to stop him when he was trying to fight Naruto. Again it's not like I believe it to be true. I was just point out that it can be interpreted like this on a contrary to what the other dude said. I am well aware of how strong Naruto and Sasuke are when compared to each other.