Open or Closed?

Perhaps I have too much free time on my hands, but I have been wondering what is the best way to leave the fifth wheel jaws (open or closed) when not in use. I had my Jayco in for service at the dealer's the other day, and they watched me prepare to back under it to bring it home. I opened the jaws to prepare for the kingpin insertion, and was instructed to leave it closed while backing in. The kingpin would separate, allowing the pin to enter, and then it would snap shut behind it. That maneuver might eliminate potential problems of closing the jaws manually if either unit is not level. I tried it, and sure enough, voila! I am wondering now whether the jaws ought always to be closed or open? Any thoughts or ideas? Perhaps it is a matter of preference, and makes no difference at all.

In my trucking days I allways leave the jaws open on my trailer(40 foot reefer)
I lineup and back with a small force to allow the jaws to lack up and then immediately try to pull forward ( If you are lock good you will not move or get some resistance....in my case the trailer don't let me move unles I activate the air brakes).
I carried lots of produce with my KW-VIT 100 double sleeper and a 40 foot reefer from coast to coast.
Also keep those jaws and fifth wheel lubricated. It help.

thanks, nomads. I know what you're talking about. my youngest son is an otr trucker. have you had trouble with the jaws refusing to close once you got the kingpin properly seated?

no....I never did.
Sometime rust accumulate and stop the jaws from closing properly.
I "Softly" jam the king ping in the jaws with enough force to activate it.
and try to move forward to see if you'r latch good. The key is maintenance.