Musical Theater question...

[PWV]

For those of you that have ever played in the pit - I'm the Chair for our High School Performing Arts Department.  The orchestra teacher came to me and asked me about this new technology available.  The rental company can "expand your instrumentation" with this software program.  Its not sequenced or Midi stuff - it supposedly follows the conductor in real time.  eg - if we don't have a clarinet, we just add that into the Instrumental Ease program and the clarinet part from the score magically joins the pit. 

My question - what if the actor misses his cue because of a costume change taking too long?  A typical pit would vamp, improvise, repeat 4 bars - whatever. How does a software program like this synch up with the human element.  Here's a link from R&H Theater Rentals (sorry, the swf file wouldn't let me copy any text.) 

Does anybody here know anything about this technology?  I think its pretty new.