We all kind of luck out because most of the time we develop on x86 CPUs and, for historical reasons, x86 CPUs pin their speculative fetches to caches lines, invalidating the speculative fetch if the cache line is invalidated. Things get really ugly really quickly if you try to develop on any other platform, such as Itanium, where this is not the case. And the longer we keep working on x86 CPUs, the longer we'll keep learning that things "just work" even when they're not guaranteed.