And these days, someone always notices. Especially if your data plan comes with a device aimed at advanced and demanding users.
And yet, they keep on making the same mistake; the latest occurence being T-Mobile's 1GB data cap on G1 data plans.
Of course, now that the cat's out of the bag they've changed their mind, and suddenly, their goal is "to provide affordable, high-speed data service allowing customers to experience the full data capabilities of the device and our 3G network," but they have to "provide the best network experience for all of our customers," so they "reserve the right to temporarily reduce data throughput for a small fraction of our customers who have excessive or disproportionate usage that interferes with network performance." Yeah, we know, why try to hide it, then?
Unfortunately, every other ISP or mobile operator is doing something similar; here's a good overview of awful iPhone data plans from Gizmodo, and don't let me get started with Comcast's data throttling practices. Will they ever learn?