The timetable, guarantees, etc. hold no relevance outside of a courtroom. Banks do not hold a trial before honoring a request to reverse a charge; they take the cardholder's word. Unless the merchant can provide a signature and proof of delivery of some item, they're not going to be able to dispute the chargeback either; the bank is leaving it up to the court system to resolve payment disputes outside of a few narrow circumstances. Nobody's going to take every funder that charges back a payment to court to prove they are not owed that refund, so in practice, everyone involved in crowdfunding has to deal with the fact that some of the money is going to disappear no matter what is written.