nostr:npub1xdl4fd0cutg0ptevld0nytcexzyw5pcdkc47zkarxkyesesrjnyssyks6q
They do and their security team used that information with spam accounts (because they were invited by the same account) to identify and ban other spam accounts also invited by the same account.
nostr:npub1ef4ycex72aykwzfs33tkkdmuwdp8ysyey256sa9jf2sx83drkl5q9z7zkr