My understanding is that AT&T doesn't throttle, they just keep adding 1gb to your usage for $10 everytime you go over.
So if you're on their 2gb plan and use 10gb in a month, that's 8gb over your plan at $10 per gig = $80 extra for that month.
...Personally, I'd rather be throttled.
Phone: LG Nitro HD (rooted)
Battery: Stock (Hyperion 3800mAH now unreliable)
ROM: CM10.1 Nightlies
Storage: Sandisk 32gb SD
--> Titanium Backup
--> Go Launcher EX
--> ClockworkMod Rom Manager
There is no "Truth", only perception and deception