twice in the same day after riding all day, i leaned my Hawk GT650 onto its sidestand to find it was up! i saved both times but pulled a lot of muscles!
years later i got off my 748 thought the side stand was down, it was not, tears ensued...
i was cleaning my 900RR and rolled it backward while trying to get the last of the wax off the front wheel, i had set the bike on its side stand but it was not locked down, the thing fell on top of me when i was lying on my back.
im sure theres more, but time doesnt permit....