The RTW ticket is 1 fare for the entire trip. As has been stated before, if you buy a through ticket on OW from A to Z via B,C, or D then your bags will through checked. If one does not buy a through ticket it is because it is you can't (award ticket + cash ticket) or 2 separate tickets with different fare basis (usually cheaper). It is this separate tickets and/or separate PNR that no longer allows through check of bags.

I would insist on through check where there is a legal connection on the same day.