I read the comments at Amazon.de about the 11S often.
Some users having cats, say the cat ignores the robot after a while.
Other say that the cat is following the robot and tries to play with.
I dont think that cats are really afraid.
They will get accustomed to after a while.
When I was young we had a tom cat.
I, stupid as I was, I took such a toy pistol and ....... bumm
I had really remorse treating the poor animal in such a stupid way after.
Whenever he even SAW that pistol he escaped quickly.