With a keybind, you are sending Alt + 3, by pressing both the Alt key and the 3 key.

If you only physically push the 3 key, never touching the Alt key.
Then you are sending two keystrokes, with one key press.

Granted, there's no way for Blizzard to know what you pushed, as the software outputs the correct mod (via hotstrings, keymaps etc) to each game, and they only see the final keystroke.
And warden shows that you are using Keyclone, IS Boxer, HKN, GCP etc, which are all fine to use with warcraft.