Never got motion sickness here.
When we visited Busch Gardens Tampa, my wife and I got on this little flat ride called "Sand Storm". She really got sick on that one. In the words of the ride-op when she came to undo the "gate" to the car... "Uh oh... We got a hurler!"
Two days later we were at Sea World. I handled 5 rides in a row on Kraken, but my wife could only do two. She wasn't sick, but she did feel a bit "woozy" as she put it, so learning her lesson from Sand Storm, she sat out the other 3 rides.
She then thought I was crazy for doing one final ride (my 6th) on Kraken after lunch (3 pieces of fried chicken, french fries, large coke, piece of cherry cheese cake). Said if she would have done that it would have been a repeat of her "incident" two days before.
-------------
"That wheel needs fixed... This thing is a piece of junk..."
- Unknown ride op on Williams Grove Cyclone