I think rust has indirectly shown that the performance impact of bounds checking mostly neglegible in practice. Even in very high performance code, I've never seen anyone turn them off for performance. This makes a lot of sense considering that on modern CPUs everything except cache misses is basically free, so a single unlikely branch compare usually just does not matter.

The only exception I can think of is accessing lots of indexes in a loop, where getting good performance requires rust programmers to insert awkward asserts or casts to fixed length arrays to get the checks to optimize out[1]. But afaik that's mostly because the bound checks impede other loop optimisations like vectorization, not because the checks are slow themselves.

[1] (e.g. when you access indexes 1 to n randomly, assert n < length before)