When I was in 6th grade a few of my cousins who grew up in a meth house came to live with me. One of my cousins was 16 at the time and a pretty heavy user of pills, cough medicine, and weed. One night my parents were out of town and left me and my cousin home alone. She brought her boyfriend over and they made weed brownies while I played video games in my room. I came downstairs a few hours later and didn't notice any weird smell or anything, but saw the brownies sitting out. I asked my cousin if I could have some (I had no idea they had weed in them at the time), and she and her boyfriend laughed and said yes. I have a bit of a sweet tooth, so 3 brownies later I went back upstairs. I don't remember them tasting weird. Fast forward an hour or so and I was so fucking high and had no idea what was happening to me. I was pretty freaked out at first but then I started to enjoy it. My cousin came upstairs a little later and asked how I was feeling, I said I felt weird, and she said "yeah those brownies had pot in them, have fun!" I was really nervous that my parents were going to get mad at me, but pretty soon after that subsided and I had an awesome night. So to answer your question, yes people can accidentally eat edibles.