It's so easy to subscribe for paid mobile phone services that you might do it without intending to: it just takes one tap on a button on the service's webpage to sign you up. Classic Yandex.Browser warns you about paid subscriptions so that you only sign up for services you actually want.
It is particularly easy to end up in this position if you get to such a site using a computer rather than a mobile device. This is because it is harder to notice small letters on a bigger screen.
According to Yandex's data, about 20% of users land on pages with a mobile subscription from their computers. One of the reasons for this is the popularity of 3G modems that are often used together with Wi-Fi routers. Additionally, pages containing paid subscriptions may open malicious extensions.
To disable malware protection: