Per the Telephone Consumer Protection Act (TCPA), you must have consent from the recipient before sending them a text - even for texts that are purely informational. Recipients provide this consent by opting-in to receiving text messages from your camp. If a parent/staff member has not opted in, they haven't given you consent to send them text messages. This could either be because they neglected to opt-in, or because they chose not to.
Admins can prompt parents or staff to opt-in to text messaging using several different methods - to learn more, please click here.