I don't know if it's the same, but i was with sprint for years, and found a work around to adding a tethering feature to my plan, and just changed some settings on my phone for it to work (similar to what some have done on their iphone). I used it for 4 years with light to medium use (i did slingbox a few times for an extended period of time) and never a word from sprint.
if there are 40 million iphones, i don't see how they would be able to accurately monitor usage. If it takes them 6 months to enter a simple code so that MMS can be active, imagine how long this would take to go find so called tethering cheaters!