I use an alternative app to communicate over Messenger and it still relies on the same APIs. That said, the app is mostly unmaintained and actually does pretend to send messages with a banned domain. Friends were discussing antivaxxers and I had just received a link over SMS from an old acquaintance to an antivax video. I tried to send it through Disa.IM and it "sent" as far as I was aware, then a few minutes later I was using FB on a desktop browser and that message was showing some kind of failure message that it was against community guidelines. When I went to look at the app on my phone, the message with the offending URL was just gone. like it had never been sent. The feature clearly exists serverside and the alternative client doesn't have a way to handle that part of the API.