I have never organized a mega-do with tons of people and events, but i have organized many medium to large group dinners, some smaller weekend do's (in conjunction with others) and of course events around artistic pursuits
I have only attended one Mega-mega do and that was the first ORD do some years ago, so my comments don't have much to do with those types of events.
I have probably made every mistake possible with organizing do's - my first one, back in April 2001, at a local pizza parlor, I didn't realize how many people drank large amounts of alcohol; I didn't realize some people had ordered separate things from the menu besides pizza; and I let myself be bullied into changing the "drop dead' date for signing up. We would up cramming into a space meant for fewer people and having some people duck out without paying at all.
I leaned my lessons quickly and so established a few ground rules for other do's I plan :
1) If I'm orgainzing the event, I pick the date and the restaurant. Sometimes I can adjust the time, but almost literally, "too many cooks spoil the broth. If someone doesn't like the restaurant or the date there's usually another choice in the future. (that goes both ways - I sometimes want to attend an event because folks I like/know are going but the cuisine or price range isn't to my liking - I have learned there's always another dinner...)
2) I tend to focus on resonably priced events for more casual dinners - under $20 /person - so we eat a lot of Chinese, Thai, and Indian.
3) Everyone pays for their own alcohol but we often split the food tab equally. See #2 above.
4) If you have been a deadbeat in the past you are not welcome to events I plan. This has actually has happened with a "serial offender."
5) For more expensive dinners or larger events,(25+ people) it is near nigh impossible to find a restaurant in San Francisco that will deal with anything other than a fixed price, fixed menu dinner. We have had a mix of weekday and weekend events, and more casual restaurants can't handle larger groups, and more "plush" places have set rules they follow. While I recognize Dovster's experiences both good and bad, the reality is when I have planned FT dinners that were on the expensive side, WITHOUT a fixed price, I have often had to either chip in more or ask for help. Tax is expensive here (8.75%); I count tips at 15%; people often underestimate how much they drink; and with that, people often underpay. Not maliciously, but often enough that I realized that my role as "bill police" affected my ability to enjoy the events I had planned.
7) The "price creep" for FT events has always been of great concern to me. I am happy to meet for snacks, lunch coffeee etc in lieu of dinenrs and I'm working on places that serve something for "happy hour" meetups to keep the costs down.
8) I personally don't like larger events (the "mega -do's") as I am uncomfortalbe in huge crowds and lots of drinking, but I salute and admire anyone who can pull off the mega PLANNING that goes into an event of that type.
6) After all that, I love planning local FT events! I like to meet new FT'ers; welcome newcomers or visitors and I of course like to eat in many of our wonderful SF restaurants.
Thanks again Jenbel for starting this very important topic.