El Gringo - is it different over there? You seemed shocked by the notion that a double bag receives 2x the fee, so I'm wondering if the ridiculous pricing is a US custom.
Kevin, I suspect El G may have opted out of reading this thread, so here's another UK-based view:
1. There is no caddie golf in the vast majority of British clubs
2. The overwhelming majority of British golfers, even club members, will never have taken a caddie. They would regard it as a ridiculous extra expense. Remember the average British golf club has an annual subscription of around £1,000, less in many parts of the country.
3. A few of the very, very high end London clubs have caddies available (though quite a few can get you one if you request in advance). Only Wentworth West, as far as I am aware, requires visitors to take one; nowhere I know of demands that members do
4. The only significant caddie culture in the UK is at the high end links courses that have lots of overseas visitors. If Brits go to St Andrews, they might take a caddie, but most would just put their bag on their shoulder, or on a trolley, and walk.
5. I've never, ever seen or heard of a caddie carrying double in the UK.
6. I personally have never paid for a caddie in the UK. I played at Dundonald, the Ayrshire links that is part of Loch Lomond Golf Club once, on 'freeloading media scum' rate, and the club's marketing person arranged a caddie for me; that was my only UK caddie experience in hundreds and hundreds of rounds.
Adam