re name: interesting!
re fields:
as I understand - the fields are there whether you shoot 25p or 50i its simply that in 25p both fields are the same. if you shoot 50i and output 25p you could well burn the comb into your finished product. In Adobe Media Encoder there is a menu item "field order" which appears to merge the 2 fields. A great way to test the field merge is with text: if it is a field merge OF BOTH FIELDS then the text appears full res but if it is a duplication of either field 1 or field 2 then the text looks very poor.