Car sharing with kids

[Blankiefan]

Looking for some context as to how people manage sharing lifts to take a group of kids places. Say there are 3 x 5yos all going to the same activity each week (5-10min drive each way). If sharing lifts, what do you do about car seats?

Use the child's normal car seat. Leave the car seats somewhere at the activity venue so that whoever is taking the children home can just put them in their car. Currently I'm taking a girl to and from brownies because her Mum has a broken leg. Her Mum kindly offered to pay petrol, but I refused as I'd be going anyway. I appreciated her offer though.

Is it not a total faff? Ours is a isofix doodah which is not a two min job to take out / put back.

As it happens we have a spare car seat so could ferry two kids safely but not a third. I don't know what the other parents would do tho.