The sort of things that are being confiscated by the jobsworths are highly unlikely to cause any harm, particularly as others have said, as there are plenty of better things provided on board such as bottles. Similarly we are no longer allowed metal cutlery on flights in to or out of the UK. The whole situation is crazy and yet it is sustained and I don't think likely to be reversed, possibly ever while Teflon Tony and his band of power mad anal retentives remain in power.
I think it is more about keeping people aware of a preceived threat and the control that allows, particularly when there isn't much of a threat around. We all know, after the Butler report how unreliable intelligence is!
The security and immigration at LHR is well over the top and yet there is nothing individual travellers can do about it if they want to fly. From time to time the level of security is stepped up so that everyone is frisked and more carry-ons are searched and then it is reduced again. We pay extra security charges to wait in longer and longer lines. Just who are the mugs here? On balance, I'd prefer to take my chance than submit to the jobsworths one more time. Sadly, I can't. It's not like we didn't have good security before - like when the IRA were active and when it wasn't needed in other places. We have nothing to learn from the farce in the US but then Tony must think we have, I heard him refer to the UK as the homeland recently - all we need now is a department of homeland security just like his pal George created and the cloning will be complete!