Google just issued a warning to all publishers:

As you may know, our tips and guidelines mention that "users should only click on Google ads if they're interested in the services being advertised". While there are many precautions a publisher can take to avoid encouraging clicks on their ads, we've found that some implementations of the ad code can lead to accidental clicks that the publisher may not have been able to predict. Some implementations that could lead to accidental clicks include placing your ads:

- In close proximity to Macromedia Flash games
- Under pop-ups or download prompts
- Near site navigation controls on your pages, such as drop-downs or menu links

Generally, we ask that you not place your ads near features of your site that your users may interact with by clicking. If your site contains elements that increase the number of ad clicks without increasing business results for the advertiser, we may consider these clicks to be invalid. "Business results" can range from an online sale to a page view. If we detect enough of these clicks and determine that the risk to our advertisers is too great, we may disable the account. To maintain compliance with our program policies and ensure that your users don't inadvertently click on the ads on your site, we strongly recommend that you move any ad units that are in close proximity to interactive site features.

As always, thanks in advance for your cooperation!

Don’t run the risk of click and miss

Some examples: AdSense issues warning to invalid clicks (w Examples)

I wouldn't say that it is a warning, more like some best practice suggestions to avoid potential false clicks.

So would I. All they're trying to do is minimize the risk of click fraud. As long as the ads are distinguishable then it won't be a problem for most people.