A new post on the adsense blog caught my attention today. Here's an excerpt from the post:

We don’t allow publishers to implement AdSense for content ads on interstitial pages. So if a user has decided to watch a video, you may not implement ads on pages saying “your video will start in 15 seconds." We’ve also seen this placement on Flash gaming sites in the form of an ad being shown to the user while the game is loading in the background. However, even if you allow users to skip these ads or close them, this placement is not allowed.
Loads of Arcade sites have an adsense ad unit showing before the game is loaded. I myself did this on my arcade site and it had a very nice CTR. However, after reading this I quickly removed it as it is 100% against adsense terms as is clearly stated in the post.

At the end of the post, they also say this:

...and you - the publisher - will be happy to have an AdSense account in good standing.
which sounds to me that they might start cracking down on adsense accounts that employ these techniques.

Part 1 of the post also talks about how the adsense units on any arcade site need to be at a safe distance from the flash game itself to avoid any accidental clicks while users are engaged in playing the game. They mention 150 pixels as the minimum distance between an adsense ad unit and the flash game.

These 2 posts rang an alarm bell with me, and I decided to make some changes to my arcades to be in compliance with these rules; I definitely don't want to risk my account over my arcades as they are not my main earners.

Anyway I thought I would share/warn other arcade owners so you guys can take action before it's too late.

The two full posts are here:
Avoiding accidental clicks Pt. 1: Keeping the right distance - Inside AdSense
Avoiding accidental clicks Pt. 2: Use the right product - Inside AdSense