Mayoral elections in London. In the US, or at least online, there's some controversy about whether it should be may-yor or rhyming with mare. You can appreciate that if you were to use the second pronunciation in, say Texas, it could be quite embarrassing. Over here, except in country areas (Gloucestershire, comes to mind for some reason), you wouldn't think it would be a problem. So you wouldn't expect the May-yor pronunciation to catch on so fast. It seems that it has, though.