Will the banks start charging us for using a debit card?

With our floundering economy, will the banks now start charging its customers for using their debit card? This has been an untapped source of revenue for banks. Now, the merchants pay a small fee for each debit card transaction. Question: if you only use a debit card to make purchaes, when will the banks start charging a debit card fee and how will this effect you? Is carrying a large amount of cash in store for our future purchases? And, is this a safe alternative?