Very serious question about IBPS PO exam and bank interviews.?

IBPS made one common exam so that any person selected in one bank, should not be able to apply in other bank but this is not happening as the persons who applied for union bank and corporation bank and syndicate bank they are now applying for indian, uco, bob, allahabad, bank of maharastra and united banks. Banks which earlier brought vacancies have yet not declared final result. their interviews are still going on. so the candidates who applied in those banks now they are applying in these banks also and the cut off is going very high. can anybody give me satisfactory reply for that.... thanks a lot.......