Call me an old cynic but this is never going to go class action and never going to be won.

The issue of daily budget and over-delivery credits applies to a 30 day period so spikes on one day will mean next to no traffic on others if you don't increase the daily limit.

Liken it to owning a restaurant, you don't know how many covers you are going to have, so you guess based on past history. If you get a bus load of visitors unexpectedly then you either go buy more food or turn them away at the door.

Only rich people from this are the legal bods.