I would think its a bit of both, then again it may just be that the two of ye are sound people who get along together!
I definitely believe that a good relationship is worth a million doses of 'law and order' parenting.
I did not have a good relationship with my own parents, they were unnecessarily strict, and in fact put me into dangerous situations with their rules - which they refused to see (as an example, I had to be home at midnight up to age 18, but some friends and I used to go to local karaoke at age 17, and it ended just after midnight. I used to end up walking 2 miles home alone in the dark because I had to be home by midnight, the rest of them could all come home together in a group - much safer).
I did not rebel or become a trouble maker, I was more interested in education, but I always resented the lack of personal freedom and silly rules that one was not allowed question. It all made for a secretive relationship where I just kept things to myself rather than let them know what was going on because they may institute silly rules with no room for compromise.
Had they been a bit more open minded and open to compromise I would have had a better relationship with them. Your son is lucky.