A vendor who gets busted will be under a lot of pressure to turn over all info that he has. He would have to turn it over if he wants to sign a plea agreement. It's an unfortunate and dangerous situation for everyone, but if you have an open order or have recently made an order from a vendor who gets busted, expect that info to be compromised. Act like it has been, get a new shipping address, etc. For personal amounts it's unlikely they will go after you. When vendors in the Farmer's Market were busted, LE clearly got some of the customer information, because some US customers received warning letters from the DOJ, so it does happen. They may not send a letter every time, but be safe and act like they have your info. They will likely only go after people ordering large amounts, though.