I take it you also avoid all roads, and do not drive then. What about doggies do you see them as a threat because 7000 people were attacked by them last year.
You really are giving up a lot of liberty for a small threat chance, its like going out and being scared of a metorite falling on your head when you are in a minefield.
Plus as many say the terrorist win by bringing the country to a standstill, can you imagine trying to get on the tube at rush hour if you search everybody? What a lovely target as well, a nice enclosed building to concentrate blast packed with bodies all queing and crowded, reckon a nail bomb and would do quite nicely in that situation, wouldn't even have to make an effort to sneak it through to a train or something, you could fill a nice 70 litre ricksack and look like a commuter, and all of your targets have nicely been concentrated in front of the safety barriers.
Anyway, it doesn't neccesarily work, guerilla units have managed to operate in countries that have full millitary occupations going on, there's whole aspects of that sort of asymetric warfare that cover not being exposed, using cell structures etc.
Tracking people and taking away their liberties for something that horrific as it is actually kills less people each year than beer is not a optimal solution, living in fear is what they want.