I see on the BBC News web page today that, according to the Daily Mail at least, out of 2000 known "fanatics" currently in the UK, only one is under any form of curfew. I guess both governments are afraid of a backlash if they are seen to pick on muslims. We had the same problems over stop-and-search when a large proportion of the people stopped were young black men while Police were worrying about knife, gun, drug and gang crime. Identifying people who matched a profile was condemned. Either way the Police were criticised.
I recall the irritation when our sons were contantly stopped in their cars when aged under about 22 and asked to empty all the junk out of the boot and door pockets before continuing to school/college/uni/work/home and getting in trouble for being late. However, there was no denying that they belonged to a category which probably had things in the car which they should not have had, and which "forgot" to tax, insure or MOT their vehicles, so we encouraged them to be polite and respectful to the Police and just put up with it until they looked older. On one occasion a very keen WPC stopped elder son's car and approached the driver's door in a very aggressive manner only to find that it was being driven by his father, which was unusual for a Suzuki Vitara at the time.
Perhaps European governments need to make it clear to the public that they will be stopped, may be searched, and may be asked to explain why they are there, where they are going and what they are doing. It is part of heightened security. So is keeping under surveilance anyone expected of posing a threat to national security, and nobody, of any religion or race, should have reason to argue with that. I just hope they stop sufficient ageing white pensioner ladies to keep the balance straight!