erck "oooo think of the last incident would you want to be the one?" Blah blah blah. Is in the same catagory as "we can't take the risk" "if it saves one life" "think of the children" "nothing to hide!" Authorities have to take risks otherwise they waste most of their resources chasing their own tails.
You will get another "7/7" no matter how many idiots you ruin, why? Becouse it's the smart and lucky ones that go on to commit effective terrorist acts.
Things like this only make success more likely, so much information is being absorbed that real threats slip past with little problem (pants bomber).
Unfortunatly there are too many terrified children in this country who jump at every single little thing, live with it, your life is unimportant and it is quite likely nothing interesting will ever happen to you, your family or friends.
The terrified children problem is also coupled with the "someone has to be blaimed, witchhunt" that we see quite well in the Baby P case, and most terrorism events.
Another thing people seem to fail to realise, is that we don't live in a particularly dangerous country. I don't see gangs armed with AK's fighting heavily armoured police in a drug war, or religious extremists beheading teachers, or soldiers on the street, bombs being dropped, riots in the streets, children recruited into militias, or any other of the terrible things that happen around the world. We'd like to make believe we're in somekind of deadly situation but the facts of the matter is you've got very little to worry about.