In CMOS logic, the problem is more severe since inputs have extremely high impedance; a floating input can settle at any undefined voltage, easily influenced by noise or static charges. This can cause random oscillations, unnecessary switching, higher power consumption, and even possible damage due to internal shoot-through currents.

To avoid these issues, the recommended practice is to always tie unused inputs to a defined logic level, either VCC (logic HIGH) or GND (logic LOW). This can be done with a direct connection or through a resistor (typically 1kΩ–10kΩ if current limiting is desired).