I've been an EasyHits member for years. I've noticed that traffic exchanges show up in Analytics (of course) and so I don't use them often but do just do a few exchanges now and again. I really don't know how much that affects things re Google but I'm hoping that just a bit of that traffic won't hurt, as long as it isn't much. And if G doesn't like it, well c'est la vie! I've given up standing on my head for them. Something to note though, is that I don't really find the traffic useful (as far as retention) but I try new things now and again for testing, to see if a landing page draws people in. Maybe that's nuts, I don't know.
Actually I don't have any success with Traffic exchanges. They all are just waste of time, All traffics are junk and useless.