Sounds like they've not taken proper measures to prevent cracking
(reinforcement, sectional grooving, whatever), and are setting you up.
"No wonder it cracked, sir, you drove onto it too soon!" Maybe they
skimped on the base prep, or slab thickness too. Who knows? Ask them
Concrete will crack. You just want it to be "under control."
Depending on your weather, you should be able to use it in a couple of