We are partnered with Wikia/Huddler and they handle the ads for us. I wish we could just run the thing without the ads but that happens to be how the bills get paid.
As Dave said, we did set it up so that for a small fee you can eliminate the ads and most folks tell me that it is worth it.
I keep the ads on for myself so I have the same experience that you guys have and on mine, the ads do not play unless I inadvertently hover the mouse over one of those video ads.
I think that is how it's supposed to work anyway. If they ads are starting without the mouse hovering over the top of it, let me know and I will check and see if this is some kind of malfunction.