AT&T users have begun to receive text messages from the carrier letting them know that they are consuming the top 5% of bandwidth. This differs from the messages they recently sent out regarding tethering, since it also applies to on-device data usage. There doesn’t seem to be a set threshold as to the amount of bandwidth a user needs to use in order to warrant a disciplinary message, but some subscribers are reporting as little as 10GB a month—which isn’t much when using services like Pandora and Spotify on your daily commute.
Sprint still offers unlimited data plans, and is expected to get the iPhone 5 in October. There is always a possibility that they will also cap usage under the increased load due to Apple users, but for now, Sprint is the last haven for bandwidth hogs.