You can also trivially suppress deprecation warnings with clang flags or pragmas, so even with Xcode there may not be a logged warning, because someone already decided "yes, I know this is deprecated, but there is no alternative, so we'll have cleaner build output thank you".
Also, it appears not _all_ deprecated APIs are causing these alerts, making matters worse. If you are using several deprecated APIs but aren't sure which ones absolutely need fixing, it would be quite tedious -- especially because the error only appears once per app.
And all of this is very easily improved with more diagnostics as the article suggests.