It's only a game ....
No, they would name their 6 forwards plus usually at least 3 off the bench. If big boppers are not lining up in the backs, there will be less need to cover for poor defenders in the backs - conditions would be the same as in general play. Teams will still position bigger backs to run at smaller backs. Hopefully, the end result is more exciting play & tries from scrumsWill we see teams named their "poorer" defending backs as forwards then?