There are lots of great ways to make the Campfire Leader's job harder for her - here are just a few . . .
Arrive after the campfire has started, and make a great deal of fuss, noise and chatter over getting everyone seated. The audience won't mind having to stop in order to shuffle up seats, wait for you to organise yourselves for 10 minutes, etc.
Insist on the girls sitting in a full circle, especially if the Campfire Leader has asked for a wedge shape - the fact that those sitting behind the Campfire Leader won't be able to hear anything doesn't matter a jot.
Sit your girls down near the front, then wander right up to the back of the circle to see your pal - no need to leave an adult with them, after all the Campfire Leader is there to take charge of them and their behaviour and safety so there's no need for you to hang around. Make it clear that it's fine to walk all over the log seats, stroll right up towards the fire, throw wood onto it, etc. Of course, you sitting with the girls, or joining in the singing yourself (or even pretending to) is out of the question.
If the Campfire Leader announces that she is going to sing a song a particular way (or starts leading it in a different way to yours) either loudly proclaim to all in earshot that she is doing it wrong, or try to get your group to do it loudly in your usual way in an attempt to drown out the others who are trying to do it the way the Leader asked.
Make it clear to the girls that joining in is totally optional, if they'd rather chat loudly or mess about than sing it's fine. Set the example by chatting away between songs yourself.
Make sure all of the girls have powerful torches, and full permission to play with them. Having 20 torches flashing into your eyes is great fun.
If there's a song the Campfire Leader hasn't done yet, barrack loudly for it to be put into the programme in every lull. Especially if it's one the Leader may have deliberately chosen not to do due to the range of ages present, or current sensitivities.
As soon as the campfire moves towards the quiet songs, get your girls to start putting on their coats, stuffing sitters into bags, shuffling in their seats, flashing torches and hunting for stray items - it helps the atmosphere no end. And the second Taps is finished (or before it is if you wish) make a noisy exit.
Make sure you avoid thanking the Campfire Leader (although the odd bit of advice on what you would have done if you were leading the campfire doeesn't go amiss). And don't even consider asking her to join you for your hot drinks before she tackles the long drive home.
All are great ways of ensuring you enjoy the campfire (but no-one else does).