app/models/trackable_event.rb
class TrackableEvent < ApplicationRecord
validates_presence_of :band_id, :trackable_tag, :user
validates_uniqueness_of :band_id, scope: :trackable_tag_id, if: -> { !trackable_tag&.allow_duplicate_band_events }
strip_attributes
belongs_to :trackable_tag
belongs_to :user
end