There are a lot of great loading screen texts that offer tips and general info that encourage good behavior on the platform, but there's nothing about roping. In particular, in regards to people who just stop playing once things don't go their way (not just slow play).

A loading screen text like "When you have priority, it's time for you to play. Roping your opponents is against the MTG Arena code of conduct" would make it explicitly clear on the platform that WotC and the Arena team are against this behavior.

Going one step further: "When you have priority, it's time for you to play. Roping your opponents is against the MTG Arena code of conduct and can result in account suspension."

Thanks for your time.