Thing is, Find is meant for searching in relatively small Strings. IMO, in that case, the cost of precreating search tables in B-M algo outweights any possible gains. It also seams to me that for the same reason, such utility, which would definitely be useful in some cases, should be rather implemented as "search class" - because you can then "compile" the pattern once, then use for searching several times.
So for String::Find, let us consider the "brute force" a feature.
I would be nice to have BM as separate thing (class probably).
But another thing is that perhaps full PCRE has similar characteristics to BM but much more flexible use... (but I might be wrong about this one...)