Mandatory, opt-in or yes/no?
Every consent form has a Decision: Required, optional, opt-in or Choose yes/no. It determines whether a family can register without agreeing and whether a no is recorded. What matters is whether the offer can take place without consent.
Mandatory for terms of participation
Required fits when the offer cannot take place without consent, for example taking part in a canoe trip or staying overnight at a tent camp. Anyone who does not agree cannot register.
Required never fits a consent to the processing of data. Under the GDPR, such a consent must be given freely (Art. 4(11), Art. 7(4)). Anyone who makes registration depend on it does not obtain a freely given consent.
Opt-in for additional services
optional, opt-in fits a service that only those who want it receive, for example a newsletter or contact about future offers. Without a decision, the consent counts as not given, and registration is still possible.
Yes/no when every answer counts
Choose yes/no fits when you need an answer from everyone in order to plan. An example is photos on the website: the supervisors must know whom they may photograph. Registration requires a decision, and a no is allowed and is recorded.