[jlgreco]

No, because in that case I am getting exactly what I expect. An ad from an ad network that the site I am visiting chose to use. That is not unexpected 3rd party manipulation.

Would you be okay with me going into coffee shops and running a NewsTweek node on their wifi that swapped out all the advertisements with ones that I could get paid for? Of course you would not, and not merely because I was not the operator of the hotspot.

[lunixbochs]

The mere existence of a NewsTweek shows how you should really not have high expectations about traffic going over open wifi.

Do you honestly think changing advertisements is the worst case for a mitm device?

[jlgreco]

Do you honestly think I was suggesting that such a use is the worst case for a mitm device?......

Once again however, it seems we are in a situation where people on HN do not recognize that there are two distinct meanings of "expect" (for the remainder of this post, the second will be emphasized). Consider the following:

  A parent of a teenager in highschool finds their child watching
  TV instead of studying for an exam.  The parent shakes their head
  and says, *"I expect you will do well on that exam tomorrow!"*.
  They expect the child to do well on the exam, but they would be a
  fool to *expect* the child to do well on the exam.

A user of public wifi can expect their wifi traffic to not be tampered with, but they would be fools to expect that.

...Now, back to the actual point at hand, in reality, tampering with public wifi traffic, not merely logging/dissecting it, is fairly rare. There is no reason to fault non-technical users (the majority of society!) for having technically unfounded expectations. Their expectations may be foolish (in this case, there is little doubt of that), but that does not give technically inclined members of society a license to prey on them.