Actually, no matter if you use quickly or bank the bankers without the Seal, you are thrown out. The only exception is if you use the far-east bank booth AFTER DREAM MENTOR, in which case that booth is open to you for free use. Or have you really discovered something new? If so, I would still say lose the Seal since it DOES weigh quite a bit and give no bonuses. After you complete dream mentor, you can bank with 'Bird's-eye Jack' without a seal. I don't think none of the other bankers will let you though.