The behavior of presence validation combined with boolean fields is a bit confusing, Object#blank? causes ActiveModel::Validations::PresenceValidator to identify a boolean field with a false value as blank. The common solution to this issue is to use the inclusion validation, but it seems a bit off for me that i would need to remember to create a specific validation to ensure presence of a boolean field - when i use a different one for any other field type.
My suggestion is as follows,
Alter the current implementation of the Validator classes to take into consideration the validated field (if it is a field) and choose a validation process that matches this field. at the moment i can only think of a boolean field as an exception that will benefit from this implementation - but i think that it would present a much more lean way to validate data layer fields.
This issue was already discussed here: https://github.com/rails/rails/issues/6953