Every event in the system carries two numbers that matter in transport: how many people gather and when they head home. That is enough to work out in advance where and at what time rides will be wanted — before anyone shows up at the rank.
Every evening at six an e-mail arrives with the events near you for the next day: where they are, how many people are expected and the window in which they will be leaving. On a quiet night nothing arrives — a “nothing today” e-mail is of no use to anyone.
When a big event ends all at once somewhere, a short text message goes out. Only then. A daily text is a nuisance and costs money, so it stays rare.
At large events someone has to keep track of how many cars are heading there. Through your personal link you sign up to an event and everyone can see how many cars are still missing — so you do not all converge on one event and leave another empty.
This is an estimate, not a certainty. Each window shows what it was built from and what is measured rather than derived — an event with a known capacity gives a far better estimate than one without. The decision stays yours, and your feedback on whether the estimate held up goes back into the system and sharpens it.
Filling this in commits you to nothing and costs nothing. I need to know where you drive and how many cars you run — that is what decides which events are worth sending you.