The three links below give an outline sketch to the availability of tracking devices around for routine use.
You can add to these a lot of other things, one way or another.
This is one reason why we have reverted to paying cash whenever possible.
The trouble is that our records will show abnormal withdrawals of cash which may encourage Whoever It Is to step up the surveillance.
At this stage I would like to declare that the reason for higher than average visits to the bathroom is the high fibre diet.
But Them Out There should already know that.