By "locking things down" I meant locking down distribution to a single app store. Certainly J2ME apps were locked down via a system of permissions, where you ha

By "locking things down" I meant locking down distribution to a single app store. Certainly J2ME apps were locked down via a system of permissions, where you had to buy a code signing cert to be granted the more interesting ones. But you could still install them from multiple sources, e.g. the phone manufacturer, the carrier, the software vendor directly, or even via Bluetooth. And unsigned apps were granted enough permissions to be perfectly viable in many cases. The "carrier policy" you mention might be a US-specific problem.