Over Usenet? Very unlikely that a casual leecher will get caught unless your ISP is doing deep packet inspection. Consuming Terabytes of data a month might arouse suspicion at your ISP, but that's regardless of Usenet or Bittorrent. 90% of good newsgroup providers offer SSL transfers these days anyways, but if someone is sniffing your line and inspecting your data, you have bigger problems than how to download the new Avengers movie securely.