I used to be the program director for a small non profit that gave kids the chance to fly airplanes. We would take off from the main airport let one kid fly then land at a side field, swap kids seats and fly back to the original field. In the spring to early summer it gets bumpy in SE AZ in the mid to late morning. sometimes the kid would urp but we had sick sacks for that in every bird. I also told each kid that if they did use the sick sack, it was theirs and they could keep it as a souvenir of the flight. The parents, weren't much on that idea. A couple kids did try to do that though. In our group anyone who had 5 kids get sick was an "ace". I had 2 to go when I left the organization. No one missed the bag. We had a very detailed instruction on the use of it in the preflight briefing.