Hmm.
I would think that the cast would be more protective. My son and I went to Universal while his arm was at a 90 degree angle in a cast from shoulder to wrist. They are more restrictive than Disney and it was only Hulk he couldn’t ride. The cast protected him from a lot.
But just a week from surgery...I mean, talk to the surgeon, but I’d be hoping I bought the insurance if I were in your situation.
I’m really sorry.