Arrow put OTSRs on every single non-hypercoaster they have ever made. I guess they just didn't want you going against the laws of centrifugal force and falling out the side when it banks 90 degreed while going fast. i really don't know. i don't really think most arrow tracks would be that good with or without OTSRs. Conclusion: just so people would feel safer, and more people would go on the ride. just a guess.