I work for a software company that lets nursing homes instantly reach all possible RNs and STNAs

that can possibly replace a nurse or aide that has called off or did not show up for a shift. And many homes we work with said that calling agencies was not an option due to cost.
What I am curios about is that one of the comments we get is that whomever is doing the searching for a replacement (most of the time calling down a phone list or asking others on the floor to pull a double) has to beg and plead on a personal level to convince someone to take that shift.
My questions are:
a) do you think that the need to beg and plead is primarily due to not being able or not having enough time to reach all possible replacements for a shift? and
b) if they were able to really notify and instantly reach all possible nurses/aides that could fill a shift, would that have more success and reduce (not eliminate) the need to beg and plead?
Thanks for all your input.