Parents do not allow their child to attend outside activities. Talk to the parents on the phone or in person and explain the event to them in detail. Allow them to ask questions. Share with the parents what their child will gain from the outside experience. Ask the parents to join the club in the activity or tell them you need their help.
Parents are apprehensive about certain physical activities.
Personally explain to the parents the physical activity their child will be doing. Share with the parents the safety measures that will be taken. Invite the parents to join the activity and reassure them no harm will come to their child. Parents interfere with their child's project or activity. Express to the parents that the purpose of the project or activity is to provide an opportunity for the child to grow and learn.