If it does come to this then I think we will be on a very slippery slope. As another pp said policing in this country is by consent and if the police start to antagonise the public then there could be major problems.
I think that the fact that policing has changed over the last 20/30 years so that there are now fewer officers on the beat and a failure to take any interest in, what to them, are minor offences such as burglary has also made the public less supportive than they used to be.
Coupled with the recent cases of policing people's thoughts and views on Twitter, if they were to start searching people's shopping bags this would be likely to damage public trust severely.
I do sometimes wonder about the calibre of the upper echelons of the police force as they seem to be constantly making pronouncements and then having to backtrack when the public react badly.
However the media also don't help and love to sensationalise this type of thing.
It is difficult to stay calm and logical in a unique situation such as this but I think that is the only way we will get through it without there being any lasting damage to police relations with the public.