"Medication not checked by nursing staff"

I was visiting my mother who is recovering in hospital. The nurses do a great job, just on this occasion left us all a little uneasy.

Yesterday a lovely nurse came in to give my mother her medication, 20 minutes later another nurse came in to give her the same medication. Where is the checking that is meant to happen? I was lead to believe that two staff need to cross reference medication given to patients. If this was a dementia ward, my mother would have been given a double dose of medication she didn't need. Very disappointing & doesn't give you much trust in this hospital's practices.