I can get tethering to work, my mom: never. My parents both got iPads and a device that isn't just online all the time could never ever work for them. iPad really set the bar on that one.
Yeah. Tethering still is too mysterious. If it's not working, which device is at fault? For awhile (pre-ICS), my Droid RAZR had a bug where it required a reboot before the hotspot would work. Of course, it failed silently and claimed to be making itself available!