Jeez, I shudder reading stories like this. I still get nervous getting underneath the car even when there's jack(s) + jack stand(s) + one or two 'just-in-case' wheels slid under there.
My kid's gf at one point had a Mercury Marquis, a great tank of a car, that had its fuel pump go. Replacement entailed tank removal. I unenthusiastically volunteered to help and, unfortunately, the kid took me up on my offer. At that point I had had little experience working under cars and hadn't even really developed a real trust in stands. I kept sliding wheels and stacks of 2x12's etc under various places to be safe. At one point the kid complained with all the stuff under there we barely had room to work!
