I talked to my mom about this last night, since a few people have been wondering. Here's the official policy (subject to change, of course):
You may leave your POS car in the field under the following conditions...
1. NO LEAKS.
2. You have to park it behind my brother's junk pile -- I mean, my brother's lot. (you know, where all the junk is - that way, the POS car will blend right in

)
3. You must come talk to me, Christine or my mom before leaving the POS car so that it can be placed in the proper location & so that we know how to get in & start it in case it needs to be moved.
4. We assume no responsibility for damage or disappearance - unless we cause it, of course. For example, if the tractor goes apeshit while I'm working on a course & I accidentally run over your POS car, I'd fix it - but if some out-of-control high school kids steal it & go drive it into a tree, that's just too bad

).