Not my best wording. The example provided (120 in a 70) presents - for me - a higher risk scenario, with certainly less room for explanation. I suppose what I'm arguing here is the nature of the rules themselves, where they come from, and how they can be challenged.
You sure don't challenge them by deciding which ones to obey and which ones not to. After all, originally there was no limit on the M1 but then one was applied due to the inability of people to drive at speed. It could be argued that limits should be RAISED as cars nowadays are far safer and can stop far faster than they could when the limits were first put in place. But that's a different argument altogether, the fact is that there is a limit which you must obey or face the consequences. (Apologies for drifting there)
If UK pilots think the rules are insane then surely the way to challenge them is to get the union to lobby Parliament, stating how other countries in the EU, as examples, do not have these same rules. Of course, since the (hmm, what's the right word here) PERCEIVED terror threat is higher in the UK for reasons I am sure Parliament would give you these rules regarding cockpit visits/locked doors/etc are in place.
After all, I guess, more of the recent "threats" have originated in the UK than in, say, Italy so the "rules" have made harsher in the UK due to these "threats". That's the argument that would be used by HMG, so until the perception that there is a risk of some nutters storming the cockpit has vanished the rules stay in place. And they have to be obeyed. End of.