With how expensive payouts to the stable of a dead gladiator could be[0], it seems very likely to me that a lot of the matches were at least coordinated, if not outright planned.

[0] "But if he were injured or killed, the lease would convert to a sale and the gladiator's full cost would have to be paid, a sum that might be some 50 times higher than the lease price." https://www.jstor.org/stable/30038038