The sensor strips were designed to support CSX (mutual capacitive sensing) as well in addition to CSD (self capacitive sensing). The TX strip will be used in CSX sensing. Currently there are driven to ground to reduce the noise. You may set this pin to shield if needed.
You may find more about CSX sensing in the following link.
CSX Mode looks very interesting. It could be used to filter out the effects of water droplets on the sensors. Condensation will be probably be more of a problem, since the entire surface may be covered.
The board I am using has a PSOC 4200 series processor (CY8CKIT-042 PSOC 4 Pioneer KIT), so I believe it should be able to support CSX.
In the Liquid Level Sensing Shield software, the 12 and 2 Sensor Version has the CapSense component which supports CSX. So I will look to investigate this further.