Years ago the father of a coworker died after his car fell on him.
I have always been careful to use jackstands, but the one (fortunately minor) scare my son and I got was when were replacing the rear brakes on his (now my) Audi A4 quattro. A front drive car with the automatic transmission in park will not roll more than a couple of inches as long as the front wheels are on the ground -- not so with all wheel drive, because of the center differential. Standard practice at home now is to use jackstands, block whatever wheels are still on the ground, and throw the spare tire or any removed wheels under the car.
__________________
"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069