@I ain't Spartacus
Funny you should mention Toshiba - if you see a banner ad of theirs at the top of the page just see what happens when the mouse cursor is placed above it (as if often the case by mistake when loading a page) Even if you have the mouse placed over the add as it happens to load it still triggers the size change though, and the ads for the HTC one auto-resize themselves even when you don't hover over them.
The most I've ever seen though are the staff here blaming ad networks for these sorts of things. They appear to take little or even no responsibility for what gets shown here, despite the fact that they run the site.
