Then again I was vomited on by a corpse and I my stomach didnt budge a millimetre...
Those projectile vomiting zombies are a bugger arent they?
I guess it wouldnt be a purely mental trigger. But it has a part to play. I still think its a case of thinking "I feel like Im gonna be sick" which escalates to "Oh god I am going to be sick" to "Im going to be sick, sh*t" which gets stronger and stronger. At some point that sick feelings going to be so strong you just feel "Right, its here its coming " *Splurge* regardless of where you are.
My one example of missing the toilet/bucket was at Chessington bubbleworks when an adult friend had sun or heat stroke I think. She was dizzy and a little out of it and we were on a dark ride bouncing up and down on water with weird lighting. Didnt help much. She must have felt pretty rough and knew that itd be a while before getting somewhere to puke, and so it went over the side. I bet that waters recyled into the sprays etc too ><