I don't think it's anyones business what client I used to create notes. If I want to advertise your client I should be able to turn it on. On by default is a big no from me, sorry. Anything my client appends to my notes without my permission is too much imo. Tags are generally not user-facing. 

To be clear, I have been very against this for a really long time, but I'm a nostr nobody. I've had it on the roadmap for my signer since the spec introduced it.

https://github.com/VnUgE/NVault?tab=readme-ov-file#extension 

 This is the thing. It's additional info in the events. Don't know if a normie user would understand that.

And what about niche clients for a subset of users tagging the events? Very easy to track them. 

 I mean... There may be some.... interesting clients, eventually. 

 If you go from client to client, it's similar to a browsing history. 

 Sure I could see you swapping from desktop to mobile and so on 

 Or from some furry dating client to the interracial porn client to the Mormon homemaking client. LOL 

I mean, okay, obviously switch npubs, but still. 

 Completely randomly chosen examples. 

 It was research. For science. 

 Okay, that's enough Internet for today.
GN 

 hahahahahaha 

 I think any client that injects non-critical tags into events by DEFAULT is wrong. Build a better UX that enables users to understand their purpose. I will continue to build tools that enable hard-core users to strip these tags before signing. Client's can break this if they want, but I hope they choose to accept the signed result as authoritative.  

 Agreed. 
I prefer relying on things that are very obviously public (zaps, replies, shares, ...) for discovery/recommendations.