The RBS thing was a bit more complicated than that.
They weren't the ones repackaging the risk on the sub-prime. That was a small number of US Banks. They did make it clear how the risk was repackaged BUT they applied pressure to the rating agencies that rated the derivatives so that they appeared less risky than they were.
There were a small number of gullible idiots at ABN Amro (a dutch bank) who were courted and targetted as buyers of the derivatives and they took the derivatives onto their books without understanding the potential exposure they were underwriting.
The guy in charge of RBS at the time (known as Fred the Shred) was a gung-ho acquisition merchant (and all round twat IMO) who forced through the purchase of ABN Amro by RBS without even the basic due diligence that should have taken place.
The due diligence checks would have brought to light that ABN Amro were up shit creek without a paddle as a consequence of the position they had taken in the derivatives that were underpinned by US Subprime debt.
When the shit hit the fan, Fred resigned from RBS and ran away with a massive pension that was part of a golden parachute deal he'd written into the contract.
I know this because I was on the inside in 2008. Ironically, I was designing a derivatives risk management system.