how can greeks buy bitcoin if there banking services are halted?
Maybe they saw what was coming/rumoured a few weeks ago. They could have withdrawn their daily maximum limit in cash every day & saved it under the bed until now 
Now they could buy BTC with cash on localbitcoins or head down to their nearest BTC ATM (BTM).
There are always ways Adam. Maybe they're selling goods or their car for BTC in desperation

right.... fuck food and stuff lets buy bitcoin with the 60eur a day.
When capitol controls are lifted greeks may say fuck going through that again and buy bitcoin.
agreed, i expect the real boom to start once the banks in greece are reopened, and it takes time to get registered / verified on an exchange, i wouldn't dare go short until about a week After the banks reopen.