Depends.
Like for example the guy who walked up the Stairs infront of the Wheelchair guy was sort of not looking that thing up from behind (from wich direction it actually looks hilarious), therefor i can get the point of helping him directly without even spending a smile.
Then again, if i was behind him, i sure as hell would have helped him up, but i most likely would have smiled.
The view was just funny, yet i feel a little sorry for that person.