I got the same problem. People who say this is OK are delusional and have no experience with large bank transfers. I totally agree with ab8989. When I receive large deposits in my bank account my bank usually asks me to fill a form to explain the source of the money. But that is the ONLY question they ask. I can fill in anything and they don't ask for any receipts or documents. If the bank suspects something they inform the proper authorities and then it is the authorities' job to investigate and ask questions. That is the normal practice all over the world. Bitstamp already has my ID card, an utility bill and all my banking information. It is enough even to steal my identity. There is no need for them to ask such idiotic questions. Now their support cannot handle all these tickets which were created by them. This is pathetic.
At my previous company, I sometimes would be required to send multiple wires in a day, often totaling $100,000-$200,000, to many different individuals and businesses. When we first started doing this, I was required to fill out lots of paperwork, and even after that, I would randomly be asked to provide more information. This was banking at one of the largest banks in the US.
What Bitstamp is doing may be a bit more than what an established bank would do, but they are trying to err on the side of caution. Quit complaining. Would you prefer they have their funds frozen and stolen, like Mt. Gox?