2GB is actually a lot for a phone by itself. I used to be on a 200mb data plan with my iPhone (changed to no data and LG Shine later) and I never went over because I never had the need to be somewhere without wifi while streaming a Youtube video or tethering or downloading lots of apps. Wifi is so much faster than 3G/4G so downloading large things on 3G/4G never made sense. Plus, my apartment, my friend's places, college campus, work all have wifi. Heck, even my grocery store has wifi for free. I can understand that if you're a business man that needs to stream a business meeting while on the go, but I'd like to think that person would be using wifi for better speeds. If you surf the web, facebook, twitter, check mail, ebay, craigslist, read news, surf OCN, etc. on 3G/4G, all that doesn't add up to 2GB unless its lots of big pictures or videos.
If you really want to tether, you might as well get Mifi. Although, I'd wait for prices to come down on the mifi device.
I'm not trying to defend AT&T (or any other mobile company) for this practice and I agree that they charge WAY too much for 3G/4G (they charge too much for texting also...
). But if you go over 2GB of data in a month, you might want to reconsider your usage or maybe change to a different provider. Like others have mentioned, there are "ways" to get kicked off a plan and switch, and there are ways to keep track how much data you use.