Ask HN: Who is using Cursor et al. for proprietary code?

I have seen quite a bit of furor over the past year or so about Cursor and other AI enhanced IDEs, and I'm curious as to how much people are using this to write proprietary code?

I'd like to think your average J. Random Hacker isn't feeding closed source enterprise code into these things to send off over an API just to get PRs out a little faster, but I know it's happening. The question is, how much, and how much should we worry about it?