IWonder, it's worth remembering that the amounts involved are often quite small. I have an acquaintance that has "bounced checks" (by using her debit card) at least twice to rent a movie for $1.00 (plus eight cents in sales tax) at the grocery store. If covering a $1.08 transaction until her next deposit is really "risking their depositor's funds", then the bank has much, much, much bigger problems.

She's actually quite hopeful that she'll be able to convince her bank that if her account is down to its last penny, they should refuse her debit transaction. She'd rather skip the movie than pay a $35.00 overdraft fee.