I know it's not a good idea. I usually go to science after pushing out a couple of warriors. If I don't find the Zulu, I'll select HBR. But usually, that's not the case and I finish up with BW given that my warriors are all spread out or I don't have time to rush three warriors. I think it's also compounded by the fact that I like to walk the settler and that is just not smart against the Zulu.