The Bid Session (or bidding session) is held usually on the Sunday morning, late enough for people to have had breakfast but early enough that the winning committee has time to sell memberships Sunday afternoon and Monday.
The chair of the following year's convention (e.g. for a vote for the 2012 Eastercon at the 2010 convention, the chair of the 2011 committee (or his/her nominated replacement)) chairs the bidding session. (In 2006, as the 2007 committee had not been selected yet, the co-chair of the 2006 committee chaired the bid).
Each bidding committee makes a short (e.g. 5 minute) presentation about their site, their theme, their experience in conrunning and any other special features of their bid (such as proximity to attractions of interest to fans, plans for special events and any departures from tradition such as "no masquerade", different dates than expected etc.)
It is traditional that a bid not reveal their guests until after the vote is taken. This is to prevent two things (I believe).
- It stops a bid winning just because they can get hold of someone special (e.g. George Lucas, Steven Spielberg and Harrison Ford) over a competing bid that could run a better convention.
- Since we want to honour our Guests of Honour, it could be perceived that the Guests of the losing bid weren't "good enough" and this would be insulting to them.
In my opinion there's a third reason, most attendees of the Eastercon (and particularly those who vote) go to the convention for the programme, to meet up with friends and to have a good time; the guests are just the icing on the cake; therefore the bidding should be on the basis of how good a convention that bidding committee can run (site, programme, ability to handle the traditional questions ("are their restaurants nearby", "is there cheap food available", "what's the no-smoking policy", "are all the rooms wheel-chair accessible", "how easy is it to get there and back", "will there be cheap diet soft drinks", "what's the room rate for the hotel", "are there enough single rooms available", etc.).
The vote at the 2001 Eastercon produced a new tradition, a committee could bid to run a convention for the appropriate year without having an agreed venue. This tradition started because there were no pre-prepared bids for 2003 so a group of fans got together at the 2001 convention and put the committee and bid together right there in the bar ... (actually I'm making up the bit about the bar, it could have been a restaurant!)
Spoof bids are welcome, but hardly ever get close to winning (with the exception of INCONCEIVABLE which beat Speculation on a show of hands but a recount gave people time to reconsider). It is considered good form to keep the presentations short and funny, to only answer audience questions directly addressed to that spoof committee (or for which there is a good joke ... some spoof bids have felt they needed to reply to every question put to any committee and, to be bluntly honest, they usually just don't have enough funny answers).
As there are no rules, in theory bids could be put forward to hold the convention on another date (e.g. Early May Bank Holiday) or to hold the convention elsewhere in Europe (e.g. Spain) or even elsewhere in the world (e.g. Florida). At some point someone will make a serious bid for one of these places and we'll see what the general feeling of UK fandom is. In 2003 we had our third Eastercon on the island of Jersey (Channel Islands) so it is clear that fans will accept a convention that they have to fly (or take a ferry) to. The next major milestones are whether fans are ready for a "British" convention somewhere like Belfast (currently "British"!) or (more importantly) Dublin (definitely not British!)
In recent years there have been very few years with two strong bids, so the vote is almost a formality in those situations, since most people would rather have a "bad" Eastercon than no Eastercon at all.
The initial vote is by show of hands, one vote per person, no postal votes, no proxy votes, and the room doors are closed to prevent people dashing in (or out) at the last moment. A number of stewards/gophers count each section of the electorate ("mob"!) and the total votes are tallied. A simple majority is enough to select the winning site. If the vote is close then a recount can be requested by any of the "serious" bidders. This vote will be taken in a manner to be determined by the chair of the bidding session, it could be another show of hands, or it could be a "division" or "lobby" vote where people have to move to one side or other of the hall to indicate their preference or even to be counted one by one as they leave through one of two doors (or however many doors are required for the number of bids remaining). It is considered very good form for all spoof bids to withdraw if a recount is required (and usually the chair of the bidding session will inform the spoof bids that they will not be included in the recount to emphasise that point).
Votes for each of the bids are counted, as are "Abstensions" (people who want to make it clear they are deliberately not voting) and "None of the Above" (people who want to make it clear they don't actually like any of the bids). For two year bidding, there is another option "Defer Decision" which means that none of the bids is currently strong enough to win, so people would prefer to wait a year and see if a stronger one-year bid is put up next time.
It is not clear (to me) what people who don't care which bid wins should do ... for example, a purely speculative thought experiement ... imagine 1000 voters, 100 in favour of bid A, 101 in favour of bid B, 202 against both bids, 103 abstentions and 494 "don't care which of A or B win". The results of the vote would have both "None of the above" and "Abstensions" beating both the real bids while the actual feeling of the room is actually in favour of bid B (101+494). But I'm sure that the chair of the bidding session will sort this out through recounts etc.