Had something similar at Weston bike meet few weeks ago - the bike my other half pulled up next to was sinking into the ground and was leaning towards his. He squished a coke can up and stuck it under the bikes stand after he picked it up. It's a tough call, not sure i'd have risked moving it for the same reasons as others have stated. *shrugs* (he only moved it because it would've landed on his bike if it went all the way over...)