Hello. I'm one of the top five percent bandwidth consumers. Hell, I'm probably in the top one percent. If a mobile isp offers me unlimited capacity with tethering explicitly allowed that is what i expect to get. Whether it's 30 gig or 300.
If they make such a ridiculous offer and can't back it up with enough capacity to support it, it is not the user's fault. If three mobile had a decent mobile broadband solution in the first place i would use it (their mi-fi home solution tops out at a tawdry 5GB a month), so tethering on a phone contract is the only way to maintain a netflix habit.
As of yesterday my connection was reduced to 100 kbps download, about 15 kilobytes per second. This is of use to nobody. They have not as yet told anyone what the trigger level is on the traffic management so it cannot be avoided except by not using it for 7 days, then trying again.
Previous poster said that using 20 gig constitutes abuse. No, it constitutes using the product i paid for. I have money to spend, if they offered me 50 gig a month at a realistic price i would jump on it. But nobody does, instead three mobile cynically troll for business by selling an unlimited product they can't maintain. Then they start moving the goalposts and things go downhill from there.
My opinion is that unlimited communications products should be banned, as they always need exceptions, even the ones that claim not to. Plums to that.