Answer: The immunity of the Capsense board to EMI and RFI can be improved by adding a series resistor between the capsense sensor pad and the PSoC pin, thus creating a low pass filter using this series resistor and the capacitance of the PSoC pin. The capacitance of the GPIO pins of PSoC is between 3.5pF to 10pF. For optimum EMI and RFI performance, use a 560 ohm series resistance between the capsense pad and the pin. Place this resistance as close as possible to the PSoC pin.
If the Capsense board seems to be susceptible to certain frequencies in the EMI / RFI spectrum, the value of this resistance can be tuned to improve the performance.