I remember when they busted Ulbricht thinking, "if they were able to catch someone who seemed by most accounts to be fairly careful (used encryption, Tor, etc.)

I remember when they busted Ulbricht thinking, "if they were able to catch someone who seemed by most accounts to be fairly careful (used encryption, Tor, etc.), how come we need dragnet surveillance?" I'd be curious to hear if dragnetting is even effective and if so, what the cost/benefit analysis is when you factor in both financial and ethical costs.