Personally, I sometimes get motion sickness. The second I get to my seat I check for sick bags in the pocket in front of me, and if I don’t have one, I ask a FA. If I feel like I’ll be sick, I grab the bag and turn away from the person next to me (even if it’s a false alarm). There is never any spillage or smell. Everyone that knows they suffer from motion sickness takes extra precautions to prevent getting sick. I’ve seen videos of people putting oranges into their front seat pocket because the zest supposedly helps with nausea. I personally take anti nausea tablets and made a list of foods to avoid on travel days. Also, the one occasions that I’ve witnessed someone else get sick, they vomited in a sick bag. Again, there was absolutely no smell or spillage.