Some ways I suspect that I am as paranoid as the next guy and have, in the past, wondered much the same as MtGM. I concluded that 'they' probably can trace me should they think it worthwhile, but on the balance of likelihood they won't think it worthwhile.
If ever 'they' do then I, as a normal average voter of moderate intelligence, am probably done for anyway, so I reckon I may as well vote anyway, and hope (but not really expect) to make a difference.