That's true, though I think it might be difficult and tedious to go through all the code of every page you look at unless you had reasonable suspicion you were being used to mine.
I was hoping there might be some tell-tale signs or other ways of checking (like looking at the processes running on your machine).
I took a look at your home page by the way. You've got some very interesting articles there so I decided to follow you. Keep up the good work! :D