At the risk of repeating myself - I don't disagree with you at all. I totally agree with everything you say.
And yes - it could be construed as unfair and singling out a certain section of society for attention but all of the areas you discribe do not have any degree of regulation over them, you don't need to do anything to ride the tube or a bus. Hence the undue amount of CCTV and other overt and covert surveillance measures aimed at users of these services. Is it right or is it wrong? Not for me to say.
Part of this I think is the idea that the government could be criticised if something were to happen where a degree of regulation and oversight exist, GA is an example unfortunately. It's all very well identifying a risk but what did you do about it is the question that would be asked when the balloon goes up.
Road traffic is monitored, ANPR is everywhere now, you can be grassed up by your mobile phone that gives your position away to 10 feet, you appear on camera approx 300 times a day in London as a pedestrian I read somewhere recently, you cannot leave or enter the UK without someone knowing you've done it. You can send emails that are traced etc. And that's just the stuff that exists to benefit the private sector, one can only imagaine what the government has at it's disposal.
I think if you analyse what is going on generally in terms of state control in the UK, you'll see very quickly, and acknowledge, that GA is the last bastion of more decent and trusting times but it's the most decent and trusting of us that ultimately get's done over by the cads.
'We're self policing and self regulating' cannot cut it anymore, sad but true I'm afraid.
And that's something worth discussing.