Oh yea, that happened once in my school. A girl confessed to a boy, he accepted, she then said she was just trolling him. He got made fun of after that.
Later it turned out she actually did like him, just people were saying stuff behind her like "Him? Really?" so she wimped out.
What a shame really.
Wait, why am I talking like I was the only mature one there? I laughed the hardest at that time! lol