In *my* not-so-humble opinion... if I volunteer to do something, I should do it. Period. It's not as if somebody promised to pay me, or promised it wouldn't rain.
Bicycling magazine this month has an article about being at the back of organized rides, mentioning that no, you just *can't* count on the sag stops having food left for you (they didn't mention them just packing it in, but I've known other rides that do that, too), so that if you think you're going to be bringing up the rear, you should pack extra stuff.
They may be volunteers, but the rides are generally to RAISE FUNDS for their club... so they *are* being paid indirectly. (And again, they said they'd do it, though if conditions were really adverse, I could understand thinking"I didn't say I'd do THIS!") If I pay for a supported ride, I should get a supported ride, at least 'til the time they say they're going to support to.
When I hear that a ride does this I don't give it my business.
In contrast, at a sweet ride in South Carolina (I think it was the Bee Buzzin' ride), we *were* the very lastest people (tho' we weren't particularly slow), and they waited 'til we were gone and then packed up... and then caught up to us and gave us another rest stop! (It was brutally hot.) That's the spirit of true service, instead of what my mother called Princess service ("well, I'm giving to those beneath me... until it bothers me, of course!") Somewhere in between would be fine...

But... mainly... AWESOME CENTURY!!!!!

You should really try to do another one... even this year... becuase uyou're already trained for it and it will be a PIECE OF CAKE!!