We don't have any data, but "would not have validated the idea" is ... perhaps not 100% accurate?
People do manage to "kinda/sorta" validate their ideas by getting email signups. Granted, it's less accurate than actually collecting CC details, but it does provide some indication. And kickstarter involves actual money, so perhaps it gives you a better idea than email, even if it's not quite as good as getting their CC. Maybe that tradeoff is worth it in terms of openness with your future customers?
People do manage to "kinda/sorta" validate their ideas by getting email signups. Granted, it's less accurate than actually collecting CC details, but it does provide some indication. And kickstarter involves actual money, so perhaps it gives you a better idea than email, even if it's not quite as good as getting their CC. Maybe that tradeoff is worth it in terms of openness with your future customers?