I strongly suspect that no criminal mastermind planning a world coup
Not thinking of quite that level of threat, Alan! More worried about the small group of 2nd or 3rd generation British Asians who decide to strike a blow for their faith, stirred on by an "imported" imam maybe. But even they are going to work out ways of getting round the monitoring and filters, lots of ways of opening anonymous email addresses and as many possible coded messages as there are meaningful combinations of words in all the languages of the world. High tech stuff, like mobile private high speed package sending stuff on FSK systems can't be beyond their capability either - IIRC the police use a similar system so a good engineer can duplicate it. (I think FSK was co-invented by Heddy Lamarr during the last war!)
As to telling us how they will do the job, asking our permission or giving us the vote on it . . . Not easy to answer that except to say that telling those whom you are seeking how and when you will do the looking seems to be a less than productive idea. Might as well not bother and say, "Well, don't complain about the deaths that may result."
Sorry, I am thinking a bit like an ex-serviceman here, never worked in intelligence but know enough about it to realise that covert action by the enemy either needs covert action by one's own side - or blowing the whole area they might be in off the map. We live in a dangerous world in some ways and I do not think it will get any better.
It takes up to 12 people to keep physical tabs on one person, that means that less intrusive ways of monitoring tend to be very expensive in terms of money and trained people. Listening to their telephones is a bit cheaper and almost as direct because it can be automated. Looking for funds being moved to suspect accounts gets more intrusive, emails even more so . . . But if having my emails monitored saves one life I deem it worth it. I have nothing to hide beyond the merely potentially embarrassing!
So, are you willing to just shrug if they stop the monitoring and a bomb blows up someone in London, Alan? Or how would you prevent that and still keep your "privacy" (in quotes because if the government aren't monitoring much of what you do you know that Amazon, Google, Facebook, Ebay etc. are doing so an either using or selling the data - is that all anonymised? No because it is reflected in adverts directed at us personally for a start!
Solution: don't ever use the Internet or the telephone system again - there yer go, fixed!
"Look forward; yesterday was a lesson, if you did not learn from it you wasted it."