BlackBogey:
I would still guess the curved pieces are for holding a few clubs as opposed to a bag, just from others I've seen used that way over here, but who knows?
Perhaps DodgyPutter could pop in and ask someone at the club ; )
I do not think Dodgy is that close to pop in, but maybe he will call the club house and find out for us.
A while back, a friend and I were debating what certain structures were, near a certain green on Olympic, he said Kennels and I disagreed. I called the course and was connected to the Pro Shop. The person I spoke with had no idea and referred me to the San Francisco Building Inspection (Dept.). I got the number and then called. They were actually very helpful after finding out why I was calling. It ended up be some time of abandoned water pumping station for the sewers.
EDIT: Nonetheless, I am pretty confident the bars are for bags, although you could use it for a few clubs. However, unless they have other such bars to lean your bag against, you might break the Royal protocol by laying your bag on the ground whilst you carry a few clubs to lean against the bars.
If you anticipate having to do that, you then have to hire a caddie who, most likely, will lean the bag against the bars attached to the box in question.