This entire argument comes down to basic human greed. There are very few things that are 100% true. However, if you were to conduct a study measuring peoples reactions to such scenarios you'll likely find that the biggest predictor of response would be financial connection.

You might turn in a good friend but not a friend that loans you money. You'd turn in a friend but not if he has the best super bowl parties. etc....

We are all greedy. Everyone, even family.

The only reason I would not turn someone in is due to basic human greed. My desire to live a stress free life. This of course is a life lesson that I've learned.

This is 100% true. Yesterday, my gf and I, were leaving the mall. As I exited the mall I fired up the truck. I set up on the aisle that my truck was in when I notice a rather large fellow walk past the passenger side of my truck, walk around the truck, past the driver side window and disappear. I drew and walked towards my truck. As I get closer I notice that the car next to me has been broken into. I walk past my truck and much to my surprise there wasn't anyone there. I was having time compression and slight tunnel vision. After a few seconds I noticed, that in the car parked two spaces over sat Mr. Problematic who I would have taken care of with my automatic had he been waiting next to my truck to take my keys. When I knew the coast was clear I told my gf to get in the truck then I got in and immediately drove off. I drove up to the first security officer I saw driving around the parking lot sipping on coffee and told him a vehicle had been broken into and where it was.

I don't feel badly about not waiting around so that the guy could be caught. I was self preserving. Also already mentioned in this thread is that rarely does punishment fit the crime.

Tom