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?
Telemetry 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.