Managed doesn't mean you're 100% safe, now days it means you're the 1 who's meant to be more copyright aware, it means the network trusts you to not produce content without permission from a copyright holder. So either the copyright strike happened because a developer/publisher was being a douche even if you had permission OR you didn't bother getting the right permissions from a developer/publisher. In the first case being managed, you can get help for that. In the 2nd case you'll be very lucky if they keep you as managed.... I'm guessing since you assumed being managed protects you from this stuff, the 2nd case happened?