The thing about giving the $$ back (let's operate under that premise and accept it as fact for the sake of this post, mmmkay?) is, funds garner interest when kept in accounts, of course. And even if you're keeping your $$ in Paypal, it is still an issue. And
Paypal's belief in your ability to pay can impact your credit score. And that's just assuming a shell game of transferring around funds without even spending a dime.
Step 1: Move cash (hi,
@Indysolo !) into your bank account
Step 2: Pay credit card debt, or buy stuff, or gamble, or get your teeth fixed, or make good on kited checks, or donate to St. Majel's Home for Wayward Trekkies, or eat at Dave's House o' Sushi. Or just keep it in your bank account.
Step 3: Somehow get funds to pay the money back, whether through borrowing against a different credit card (a sign of a major financial problem, folks), or taking out a bank loan, or gambling winnings, or donations, or selling props or CDs or whatever, or a gift from dear old Mom, or salary from a real-live job (what a concept), or you found it in the street. Whatevz.
This is not honest. This is not ethical.
Even if you pay it all back. Even if you pay it back with interest. And while you don't have a specific fiduciary duty when it comes to crowdfunding moola (
although I bet that's coming), this playing 'hot potato' with the donations is ethically questionable at best.
In da law, we keep escrow funds. Those are for things like a client buying a house. The big ethical thing is to never, ever mess with escrow. And lawyers - particularly those with some sort of addiction problem, I have noticed - are disbarred over touching escrow funds.
EVEN IF THEY PUT IT ALL BACK WITH INTEREST.