The block of garbage at the beginning of the handshake is, as far as I can figure out, a bandwidth test. The pattern is intended to be resistant to compression, so as to more accurately measure the real throughput of the client's connection.
Flo writes "According to Fefe, a German blogger, U.S. officials copy hard disks of laptops upon entry. They even insist on the disclosure of passwords so they can decrypt files. Allegedly they even take people into coercive detention to retrieve the passwords. Fefe's sources are one member of the (German) Federal Office for Information Security (BSI) and one employee of SAP. He also claims to have received confirmation for this from "two other large companies"."