The analogy I use is to compare the unlimited data plan to an all-you-can-eat buffet at a restaurant. The restaurant prices their meal based on what a typical person will eat in a single sitting. Some people will eat less, and some people will eat more, but it averages out. However, if you come into the restaurant with 4 of your friends, buy one all-you-can-eat meal and everyone eats off of one plate, then you are violating the agreement. If you bring a couple of duffle bags with you and load them up at the buffet so you can take all the food home to fill your refrigerator, then you are violating the agreement. If you come in morning and camp out in a booth all day grazing off of the buffet, then you are violating the agreement.