I think you overestimate how easy and effective that is. The total entry guard bandwidth in the network is 1200 + 800 = 2000 MB/s [1]. You need to add 50% bandwidth to the existing network to become 33% of the final bandwidth, so that's 1 GB/s. Assuming the attacker adds very high bandwidth, 30 MB/s relays, he would have to add over 30 relays. If 30+ relays at 30 MB/s suddenly showed up on the network, people would notice. Then the attacker would have run to these relays for at least month, and what would he get? A list of people accessing SR. A list of tens of thousands of people. What could he do with it? Accessing the market doesn't prove you did anything illegal. It doesn't tell you who the vendors are. It would still be incredibly costly to perform traditional police work to identify the high value targets. Once again, the large crowd protects you. 1. https://metrics.torproject.org/bwhist-flags.png