Fair point actually - didn't consider that the cost is embedded. That said, How often are those the data hogs? (Anecdotally from myself, I rarely come near the data caps). My assumption is that even today, video apps are the most data intensive - outside of those, are folks hitting their data caps on a regular basis?
You gotta have a data plan to access these from anywhere. Most schools don't have wifi. So, the actually can cost more than phone calls, letter etc...