I heard that cold wallets can be hacked. But never expected BTER to be hacked, specially because they are expected to keep it much much much more secure.
You heard wrong ...
Yes, it is almost impossible to hack a cold wallet because :
- it is offline
- you don't know which wallet they have used,
- again , it is "offline".
If they had a malware/virus on their offline pc, in this case it was possible to "hack" the cold wallet. However bter has opened.