*not a confession* I'm sorry if i'm bothering you since this isn't a confession but may i ask you if you know if students that went back home for winter break were allowed to use magic? Thank you so much!
no! no underage magic outside of school! However, the trace is a very fallible thing so even though they weren’t /supposed/ to, anyone who lived with/around other magical people could use it without getting into trouble because they basically left it up to the adults in your life to keep you from doing it. The trace is used to track underage magic, but it actually tracks magic that happens NEAR an underaged person. So when Dobby used magic near Harry, who lived in a very non magical area, it registered it and they assumed he’d done it.
however if you lived with the Weasleys, for example, it would be up to Arthur and Molly to keep you from doing it because everytime THEY use magic around their underage kids it would set off the Trace. And so it is effectively useless.
Like, I’m sure Lucius and Narcissa let Draco use magic all the time at home xDD but its a parental thing so. yeah.