He reaches at well, stopping his father before he can touch the collar. The only time anyone else has touched his collar was during maintenance and those had been worker units, placed int he tower to do this sort of thing. That was just normal circumstances though, not even thinking of the ultraviolet fluid Jason had filled it with when he brainwashed Legolas.

"My senses have been deceived before. It's only too easy for them to deceive me again."

Who 'they' are, he doesn't mention but the tensing of his shoulders told that they weren't anyone he cared for.