I did use it in the past using the Rust library Serenity [0] (unofficial library ofc) to make a geoguesser-like bot [1] for a private server with friends. Pretty simple to use actually! Do note they have some pretty harsh ratelimits when it comes to API calls though, so pay attention to caching when fetching data (not likely to be an issue for your usecase at it'll mostly be server-sent events.
[0]: https://docs.rs/serenity/latest/serenity/
[1]: https://github.com/Tuetuopay/bot-ticelli (don't judge, this was thrown together between amongus games during lockdown)
Indeed since clients have a websocket connection to stream incoming messages, it should be nigh indistinguishable for them from a regular clients.
Also, the API abuse they are worried about is spam and scams, so just pulling out messages is likely to be the last of their problems.