One of the ways that you can find out whether a child has magic or not, is to see whether they are able to use it subconsciously, such as by defenestrating them, and seeing if they stop themselves from being killed. But once they get their wands, that use of subconscious magic seems to stop entirely.

Logically, you would expect students to fire off similar magic when their lives were at risk, or their emotions ran particularly high. Is it a function of having the wand that stops it, or is it just a matter of that only happening for really young mages, and that they learn to control themselves as they enter childhood?