I was able to replicate your experience this morning. Without a network connection to Google Play, the Android tablet could not launch SmartOffice2.
However, if I launched SO2 with the device connected to the network (so the license could be validated), after leaving the network, SO2 continues to launch. I will continue to test throughout the day today, but we think the validation will last 24 hours.
As a work around until we can extend the license lease time I would recommend that you launch SO2 at the start of your day before leaving the network. That might allow you to launch SO2 successfully when you are on the road.