I drove up to Michigan from Texas with an infant in the car and I doubt we went more than 5 minutes without checking on her.
As most responsible parents or guardians would. I have to wonder, did this poor child cry? Did she make any sound or just wither away? Babies generally let you know when they are not happy which leads me to believe the parents are just like my neighbors and just allowed their baby to cry with the hope it would cry itself to sleep. While that's not always a bad thing, in a hot car on a 100 degree day requires a more proactive approach.