After Sep 11 the adminers that make these knee-jerk rules just went for the easiest media friendly option, barricade the flight deck at all costs without really looking at the security issues. The Pilots are the cheapest and easiest group to deal with.
For instance, Captains at the metal detector getting their toe clippers confiscated!! Why? What was he going to do? Stab himself? Hijack himself?!!! There's a great big sodding axe there for F**KS sake!
Imagine this, a jumpseating Pilot in full uniform, travelling to work, denied a jumpseat by a fellow colleague, when this Pilot is going to fly the aeroplane on it's next leg!!! Madness!
Who is more likely to be a terrorist/nutter, the wife/children/colleagues of the Pilots or, for example only, some 3-month-in-the-company caterer with an unhealthy interest in Islam?
Indeed a security barrier between each & every crew member is what they'll dream up next!!!
As for the unfortunate next generation of potential pilots, buy some shares in that company that does the From the Cockpit video series!!