I don't think that good parenting is constant surveillance 24/7. Aim of good parenting should be to finally enable them to look for themselves. 7 and 10? If they cannot be left alone for 10 minutes, when can parents start to let their children alone? At 18? 20? 30?... Maybe that's why so many stupid adults are running around these days who really should not be left alone.
Turning off the DVD, getting children out of car, discussion and whining ("why can't I stay here and watch? I don't wanno go that stupid store!"), will take more than 10 mins. Unnecessary stress for both, parents and children. I wouldn't leave the key in the car, wouldn't do it if the car is parked in a sloped road, and would lock the car.
Of course it is possible to construct any kind of lurking dangers that can threaten them. But remember, you can die while walking your dog
"We used to play in the woods when I was little too. But life was different then." Not really. Standards were different then. Todays parents would start discussing the dangers of falling trees, dangerous rivers, diseased animals, possible broken bones etc.
I doubt there is a "right" way to do it, but making parents to slaves for their children surely isn't. Over-protectivness is widespread these days and seems to result in todays people - not able to care for themselves, unable to take any responsibilities, and crying for laws and government to protect them against anything and everything including their own lazyness and stupidity.