He made some purchases on the old ToS and some on the newer ToS. So he did agree to forced arbitration on the bulk of his transactions. That's not saying that the first transactions should be grouped in (or that forced arbitration should ever happen) but this isn't just a company changing the ToS later without him ever agreeing.
>The question is, was he made aware, that his previous agreement will be changed when he was giving some more money?
Any new pledge could easily have a little tickbox "I've read and understood the terms & conditions", I'm not sure if Kickstarter has one but I've seen such boxes pop up everywhere.
