You are more at risk driving to a buddies house with an 1/8 in your pocket because if you get pulled for anything they have the right to search your address especially if your driving.

Can't see many suppliers selling their customers out as there isn't yet an endless supply. Also the data held by the banks & PayPal etc.. is covered by the data protection act's & giving it to the goverment would be in breach of that..

If your already being watched & they have sufficient for a search warrant then they could get warrants to see any financial records but there is a few regs to prevent fishing trips.