Every campaign passes an automated review before it goes live. The rules below are exactly what the pipeline checks. No surprises.
Pledges are held in escrow in full. Hit the goal and funds release to the creator at the deadline; miss it and every backer is refunded automatically. Example campaigns cannot be backed at all. One exception: an 'open goal' campaign sets no target, so there is no miss-refund and whatever was pledged goes to the creator. The campaign page says which kind it is before you confirm.