Despite what politicians portray, most Kenyan tribes are welcoming to outsiders. However, there's a Luhyia house that does not like/trust visitors. Not because they discriminate against tribe, but because that's their culture. If you're offered chicken and ugali for lunch, you're welcome. However, if you're offered rice for lunch, you're not welcome, so run!
Note: If you're offered githeri or rice for breakfast, you're safe. Luhyias consider any food other than ugali as desert or an accompaniment.