When the runway is wet which is often enough, wet runway performance buffers and techniques should be applied to the aforementioned corporate jets. Simple stuff like reduced payloads, higher flap settings and minimum V1 SHOULD mean that an over-run is still very unlikely. But of course it COULD still happen. Through all the years they ran L188s, DC9s and B727s ( which were seriously performance-limited at that airport ) I don't think they ever had an over-run. Maybe the historians know otherwise? So of COURSE a frangible concrete crash barrier is an excellent idea. All airports should have them. But, when I drive past on the freeway it's not the jets at V1 that I think about; it's that fully-loaded Chieftain already airborne and coming straight at me....