Greeks may send money abroad to their friends to buy bitcoins for them. They could use insured courier packages for transferring the money.
Two greek friends of mine managed to withdrew their euros from their bank account with the help of bitcoin.
They used their internet banking to send euros to btcgreece.com (greek btc exchange with a greek bank account). There must be no limitation for transferring money from one greek bank to another greek bank via internet banking. Then they bought bitcoins and withdrew.