i'm in canada with cold harsh winters, so battery boosting is quite common around here, and yes i've witnessed another tech boosting a 3.8 GM (i was actually in a new car waiting for its engine to heat up so i could put the blower at work for the interior to get at a normal temperature before entering the shop to install a remote starter....because at -15°C plastic trims are very fragile + entering the shop with a car that cold, the humidity from the wash bay condenses on all interior surface and then freezes....so you get a layer of ice everywhere inside ! )
.... so he tried cranking but battery was completely dead (a trade-in that was left standing for a long time), he came back with a booster pack, cranked it (took a while but not too long either) and then the gunfire sound with plastic parts flying !
we ordered the intake manifold from the junkyard, replaced it and car ran fine.