Really you will have to talk with that particular club's leader because each club will be run differently. Our dog club prefers parents to stay, we might use them as posts, making sure their children pick up after their dogs, etc. but the one parent always goes on a bike ride during our meeting or leaves UNLESS we tell him he must stay!
4-H is volunteers. During extra outings such as Bake sales, etc we require parents to help in someway. Bake, take a shift,etc.