Would a filter like this make it seem less likely that they're harvesting PII? Why would they need this if they were tracking all user queries with a finer-toothed comb?
replyIf by a "finer-toothed comb" you mean telemetry then I don't quite see it as comparable to this situation.
replyTelemetry is disclosed in privacy policies, it can usually be opted out of and if not that, then it can be blocked by a firewall. Steganographically fingerprinting customer's network routing when they consented to your tool reading a txt file is a different problem. Anthropic has demonstrated capability and willingness to embed arbitrary obfuscated data in their comms streams and that's a dangerous precedent to set.