Alerts must be actionable. If you tell me "Foo: Bar happened. Quux!" and I can't do anything about it ("throw your Foo away" is rarely an acceptable option) then I just feel like Linux is pointlessly screaming at me.
It's worth recording and making available the information to anyone who enquires, but that's about it. I'd say it's like the occasional deprecated API feature, those get mentioned in dmesg but they aren't (in any system I've seen) pushed to desktop notifiers etc., because users who can't run dmesg are most likely powerless to fix them, and generally an upstream will already know about it and be in the process of developing a fix.