"Why join the e-gate queue at all if you know it is not going to work ? AFAIK, the people directing you to the e-gate queue have no power of arrest and have probably been told not to touch a passenger physically without consent for fear of a legal claim of assault. Everything will be on camera, so if they start pulling or pushing you physically, the evidence is readily available. Would be extremely difficult to make a charge of terrorism stick against a person refusing to join the e-gate queue and choosing the manual queue instead."
Because I want to get out ASAP - not spend 4 hours in a small room waiting for an expensive lawyer to "enforce my rights" - and be splashed all over Social Media