No, you wouldn’t notice, especially if you didn’t know what to look for. The flavour change is pretty subtle, especially in something like a chocolate brownie.

And the effects of edibles come on very, very sneakily. It generally takes around half an hour before you feel it at all, so it’s very easy to not even realize you’re high, especially if you weren’t planning to be, and perhaps don’t have much experience with cannabis. If she maybe ate two or three without knowing what they were, she could easily walk away from the party feeling fine only to end up completely whacked out of her gourd on the highway.