Got a bit of an issue, one of my best merchant affiliations has just changed it scripting. This means that when their advert shows on my page it re-boots the page and opens it at their own home-page. I have been assured that this is accidental (something to do with the javascripting used for the advert which includes a drop-down menu) and that they will fix it but I have no idea how long this has been the case and how many users have 'accidentally' been forwarded to their site when trying to reach mine.
This also leaves the bigger question of being banned by Google for re-directing. What happens is, if a user clicks through from Google and lands on a page that has this particular merchants 120x400 banner showing, the page re-boots itself and goes straight to that merchant's site.
That's considered spam by Google, right? So are we in danger from merchants who (either by accident or on purpose) create banners that mess with coding?