I was a participant at IOI in the early 90s where we had free seating in excursion buses (anyone could get into any bus) and it was chaos to try to ensure that no one was left behind. The solution at the time was to allocate delegations to buses, and we have used that system since then - but could modern technology offer a better way?
At IOI 2011, I skipped the Leaders' excursion to Bangkok and joined the students at the Ancient City.
First, the buses were supposed to leave at 8, but left at 8:30 All the buses arrived together at the Ancient City, and we then all waited while several people used the toilets And then there was another delay as we waited for the tram cars that were to take us around. And there was a similar delay in the departure time as well.
What if, instead of allocating delegations to buses and waiting for all buses to fill up, each bus were to leave as soon as it got filled? so the people who make the effort to be ready at 8, leave at 8? people who come at 8:30, can leave at 8:30 It would be fairly simple to have an iPad application that, with one iPad per bus, would allow delegations to "check in" to the bus, which would allow a coordinator to have an overview of who left on the excursion and who was in which bus.
An additional benefit of this would be that there would not be a queue for toilets or entry on arrival at the excursion site, and neither would there have been a delay for trams.
(of course, personally I would have preferred to rent a bike and cycle around rather than go on the tram - and if such options could be provided it would be nice; i.e. those who want to explore on their own, please pay XXX for a bike, or you can walk; if you want lunch please be at this place at this time, and be at the bus between such and such times for departure)
Other considerations I know that in some countries we have had police escorts during excursions, so this system may not work too well in such a situation What if some people don't want to go on the excursion at all? In Thailand, they would not even have had the opportunity to have had meals at the hotel, because the hotel was not expecting them to be there! But if we want to promote the flexible agenda option, then it may make sense to facilitate meals at venue for people who don't wish to participate in excursions (e.g. they are tired, unwell, or simply not interested in that particular excursion).