I was in Yemen yesterday. Now the news and the Yemen government are saying it was a mortar attack aimed at the US embassy, but missed and hit the girls school next door. Apparently the mortars were fired from a nearby rooftop. In general, Yemenis that I met were disgusted at either attacking the embassy or a school. Out in the countryside, every man I saw had an assault rifle, mostly older Russian made AK-47s (kind of like every woman in Houston carries a gun in her purse). So I think that the answer is no, mortars are not used to settle personal disputes. However, there was a report of one village refusing to register their cars and pay the license plate tax and they used mortars to register their displeasure with the government. So mortars are probably more of an anti-government (theirs or ours) type of dispute.
I have not been in the middle east since the mid 90’s. I was being facetious about the settling of personal disputes with mortars. I appreciate your info though. BTW what is a cheese head doing in Yemen? Are you staying at the World archipelago?