A new twist on work hours

Work schedules are usually cut and dried.  The worker is scheduled for certain hours on certain days.  There is an implicit understanding that the worker may not be able to report in case of illness or accidents and that the job may not be there in case there is a flood or power failure.

Recently NPR ran a story about a new form of work scheduling at retail outlets.  Employees are still told to come in for specific shifts, but not as many as before.  Then they are given other shifts where they are instructed to call in two hours before to see if they are needed.  In essence the employees have to keep their schedule open so that the employers have a call option on their services.

Companies are selling software packages to help employers make better scheduling decisions.  According to NPR's account, the software advises managers to call more workers in on days when sales are running strong and vice versa.  Obvious problem #1 -- just because the noon rush is big, does that have anything to do with afternoon or evening sales?  Obvious problem #2 -- the focus here seems entirely on cost control; what about losing sales when lines get too long?