The night before I was due to take my first blackbird in for trade in evaluation (after a last ride) I dropped it in the shed. I shoved my leg under it to cushion it's fall so there was no damage but it really pissed me off. Cause was the bike rocking off the sidestand as I got off. I now always leave it in gear and rolled forward against the gearbox so there is no chance of it happening again. Yes the OP is 100% at fault. Just like I was, but we are human and we make mistakes. My sympathy and understanding to the OP. We can only try to work out what went wrong and put in place a system to stop it happening again.