Way to miss the point
Sophos equates hidden tracking activities with loyalty cards?
How do you stop web tracking? No-one really knows - you probably can't eradicate it 100% without making the web useless.
How do you stop loyalty card tracking - don't use the card - 100% effective and simple.
I think the reg should be looking for a new regular expert commenter on security issues - sophos clearly isn't taking it seriously any more.