Tristan, i don't think it is just a family thing. My point is that as cultural influences changed in Jawa so did the attitude towards the keris. As you point out, you have seen pictures of soldiers riding into combat with tombak and pedang with keris at their backs.It would be interesting to know what period those drawings date back to. Certainly the tombak and pedang were always considered the superior and preferred weapons of war. The keris was brought into battle for more talismanic purposes. Still, in a pinch it could be used if you were otherwise disarmed. I don't believe the keris was ever intented as a weapon of war. This doesn't mean, however, that there wasn't a time when people might end up fighting with keris. People get into fights everyday and if the only weapon you have on your person is a keris (and back in the day every male carried one daily) then it is likely that it could get drawn in anger. I think there came a time (i couldn't say when, but probably some time after the fall of the Mojopahit kingdom) when the use of the keris in this way became strictly taboo in Jawa. It is probably best in enforcing a taboo to adopt the belief that it has always been this way. But since we have written observation from early periods that it was not i find myself questioning this assertion.