If depositers money is frozen, even for one day before it's again restored, word will get out. That's because at any moment hundreds of depositers are accessing their bank accounts for cash withdrawels or using debit cards; payees are covering checks and electronic banking contracts by depositors to pay bills.

Every bank in the country would face depositors demanding back all of their precious money: the bank run of the millenium.

The FDIC that insures deposits would default. Hilarity would ensue.

These days especially, the banks must know what would happen if they froze depositors money at even one branch of one bank.