I agree, however, million of kids have ready access to liquor kept in the home, and generally it's not under lock and key. Unlike pot, alcohol can readily kill a kid.
Putting the weed in brownies is equivilent of storing your liquor in a pop bottle, or mixed with the jug of Kool-Ade.
It isn't the possession that is the problem; it is the "storage" method that is the problem here.
Reminds me of when my dad put Ex-Lax in the Hershey's wrapper, then TOLD his Bedouin laborers that it was "his medicine" and that it WOULD make them sick if they stole & ate it. He never had his candy bars stolen from his lunchbox again!
I knew that someone would have to whine about the unfairness.
Oh, I know how easy it is these days for kids, however,a five year old opening a bottle of alcohol and liking the taste is a bit different than finding and eating a chocolate brownie laced with a drug.