Today the WSJ headlines the Sokol/Berkshire matter as a "scandal." It certainly is a scandal.
Compare this, also reported in today's WSJ, where the FBI arrested a lawyer for years of insider trading on information he gained from merger and acquisition cases in respect to which his law firm provided legal services. (See this for a parallel article that does not need a paid subscription.)
Maybe the reason Sokol has not yet been arrested is that you get one bite of the apple free. The lawyer in the other case took several bites. Today's WSJ article suggests, however, that the peculiar circumstances of the Sokol case may mean that Sokol slipped through a loophole. But we shall see.