OK, then we live in different realities. I doubt even 2% of my friends know how to make mayo from scratch, yet something around a quarter repeat this myth.
When I was a kid I took a sack lunch to school. It sat in my backpack for 6+ hours until lunchtime. Has something changed? Is this uncommon now? I’m very surprised by this question.
Cooked meat loaded with preservatives? I’m sure it can last half a day in a lunchbox.
Raw chicken out for 2 hours? Throw it away.