The situation
A handful of dates, limited places, catering included. The kitchen needs the number of people and the dietary requirements, and it needs them beforehand.
Registering for an event
A tasting, a workshop, a factory tour: registrations are not a purchase. They still need reliable numbers.
The job
Where the built-in tools stop
A free-text "notes" field delivers both somewhere in the middle, or not at all. A number stays a number only if the field is a number field.
This is what the form looks like
The names of the companions hang on a number, the follow-up on dietary requirements hangs on a multiple choice.
What matters here
A condition on a number
Number fields know "is greater than". From two people on, the field for the companions' names appears - with one person it stays away.
A condition on a choice
Multiple choice fields know "contains". Whoever ticked something under catering is asked about dietary requirements.
Limits on the multiple choice
A multiple choice can require a minimum and a maximum number of ticks. That enforces "at least one" without turning it into a mandatory field.
Where it sits
As a block in the shopping experience of the event page. If the event exists as an article, a product assignment works too.
What comes back
Date, number of people and catering as columns of their own. The number of people is a number, so it can be added up.