Excellent post, however most of these I avoid out of common sense!
I have NOT come across any case where someone has been banned irresponsibly in theory.
It only hints that giffgaff might need a better detection mechanism. It has been told numerous times that it is not "how much" it is all about "how" you use internet on giffgaff. FUP is only good when a network wants to monitor it "how much".
Customer A : uses 10 GB in 30 days i.e. 330 MB/ day on his mobile. It is a lot when you look at some network's monthly allowance of only 500 MB. Now this customer is least likely to be banned by current giffgaff detection system.
Customer B: Uses 10 GB in 15 days on his mobile using streaming services occassionally or file share etc. - nearly twice as much as Customer A. He is likely to get a ban if he isn't careful with how much he streams or if he does what Customer C will do.
Customer C: Watches 30 hours of streaming movies on his 5" tablet with his girlfriend in his arm to show off his cool phone and network. He uses 10 GB in 30 hours. He is very likely to be banned by the time he finishes day 1 of fun.
Customer D: He uses the goodybag in his iPad or plainly tethers his laptop while on an amazing picnic in Hyde Park. He wanted to play cool tunes via his Zune Music Pass and play smart DJ to his friends on his phone, but the speakers were rubbish on his phone. So he thought to just stream youtube videos on his laptop using unlimited internet on his giffgaff SIM. He uses 10 GB in 3 hours. He will be banned in a giffy!
Giffgaff ideally is expected from customers to distinguish Customer A, B and C against D. D is only the bad one according to most of us. But current scheme of auto-ban isn't clever enough to distinguish between C and D for sure, but many a times even B is treated like C and D.
"Dear Giffgaff, it's only D who is in the 1%" is what you would want to say. But if you are Customer A, you know you are safe. B and C, I see your frustration and although all the happy customer A (probably 80% of us) don't care, the other 19% of B and C are going to keep asking giffgaff to make it better.
For giffgaff it is 80-19-1 here. If I was giffgaff and I had to choose between
80 -19-1 (where 19% if write to an agent will get it sorted back anyway) - then I will choose this setup instead of using FUP.
However if 19% slowly becomes 29-39% - Giffgaff should be worried.