"Visiting/birthing partner atrendance"

My best friend is currently in the ward. Has been for a few days now. Her main birth partner is her mum and I am also her birth partner. It is her first baby and she is petrified inside.especially being that the baby is going to be premature. Unfortunately a couple of the days her mother (and main birth partner) wasn't able to be with her and the expectant mother asked if I could stand in being as I am on the list as a birth partner and am her best friend. I obliged and sorted out lifts and when I arrived and buzzed to be let in I was asked if I was the birth partner. I don't lie so I openly said that I am for today because her main partner and mother is unable to attend and so I'm stepping in. I got told she is not allowed to swap and change birth partners and that on this ward she is only allowed one partner until.she is taken upstairs then she can have two. I was given quite a lecture about this but none of us were informed about any of this when she was first admitted so if they had not have let me in she would have been all on her own. I was allowed to stay but I feel the staff member was very rude and quite harsh. I sat quietly all day and caused no bother to anyone. It eased my friend to have me there and helped out her mother aswell because she has a poorly husband to care for too and cannot be there at all times. I do not understand what harm it causes to have a change in birth partners. There are only two of us, we have not been there at the same time crowding the bed except during visiting times then obviously we are both there. If it means she is not alone and worrying and we keep quiet and out of the way and make sure we announce who we are then j don't know why the two of us cannot share out the role of being partners. If anybody is admitted to hospital and have staff members being as awkward and short and difficult with the visitors/birth partners as I and her mother have had then the patients will be very lonely because it was disgusting. Her mother got quite upset and shake at having this stupid rule.enforced to her. Can you explain what the harm is in having me replace her main birth partner so as not to leave her alone when her mother clearly had her own life and responsibilities she needs to take care of at home.she cannot be everywhere at once. The attitude stinks.