Penalties will be imposed if a publisher is found to have misrepresented the ad placement. Depending on the severity of the misrepresentation, the publisher may lose payments or have their AdSense account disabled.
Advertisements are just as important as content. When a user visits your app to check out your content, he may view or click on a few ads on the page. This means that the content comes first. If a user does not find anything relevant as soon as the web page loads, he will leave.
Learn how frequently users visit a page, what type of content is most popular, and if there are any navigation issues. The answers to these questions can help you improve your app's landing page and decide where to place advertisements.
Users should not be confused between advertisements and content on the app. The ads should have a distinct look and feel, border lines, and a colour palette that differs from the content. Otherwise, Google will prevent such advertisements from appearing.
It is always advisable to run tests for various ad units. Choose the ad type, format, and placement based on the results of the tests.