Redheads will stay near the substrate,but since they have "personality" at times they will come up to greet you. Feeding time for sure once they recognise you as the delivery boy. Honestly,long as they are well fed don't think they would bother them since they are mostly sifters...but a small enough "stupid" Rummy might get eaten.
Full grown Rummys shouldn't have much to fear from juvi Redheads,and growing up with them would pretty much have them not viewing them as food.
Just think about it.