ELUA for interstitial ads?

EULA for interstitial ads is necessary now? Look at ‘Disclosure of Ads to Users’ Ads | Android Developers
Ad networks say me: there’s no need for a EULA because we only do advertising inside the app.
What do you think about?

Those are just best practices I believe. You are not “required” to inform users of ads within the app.

Here are what you “must” follow, as stated in the new Google Play Developer Content Policy:

Ad Policy
The policy below covers all ads that are implemented in and bundled with apps. These rules are important in maintaining a positive experience for everyone using Android apps from Google Play. Be sure to check back from time to time, as these policies may change.

Developer Terms apply to the entire user experience of your application
Please be aware that Google’s Developer Distribution Agreement and Developer Program Policies (together, “Developer Terms”) apply to each application (“app”) as well as any ads or third-party libraries bundled or made available through the app. Offer your users a consistent, policy compliant, and well communicated user experience.

Ads are considered part of your app for purposes of content review and compliance with the Developer Terms. Therefore all of the policies referenced above also apply. Please take care to use advertising which does not violate the Developer Terms.

Ads which are inconsistent with the app’s content rating also violate our Developer Terms.

Ads Context
Ads must not simulate or impersonate the user interface of any app, or notification and warning elements of an operating system.

Ad Walls and Interstitial Ads
Interstitial ads may only be displayed inside of the app they came with. Forcing the user to click on ads or submit personal information for advertising purposes in order to fully use an app is prohibited. A prominent and accessible target must be made available to users in any interstitial ad so they may dismiss the ad without penalty or inadvertent click-through.

Interfering with Apps and Third-party Ads
Ads associated with your app must not interfere with other apps or their ads.