Yes, that is true, but only if you are running from a single power source. This is true of my whole AC, as it is all electric with no vacuum system.

Part of my background as an engineer was development of missile tracking and Range Safety systems for the Navy testing of submarine launched ballistic missile. The systems we designed had two critical characteristics. 1. No single point failure could jeopardize the mission, property or life, and 2. No critical failure could go un-monitored.

If you power the ignition systems from two independent power sources (alternator and batteries sets), size them to run your critical minimum power need and monitor the health of these sources you should be business. I've a 60A and 20A alternator, each driving independent 28vdc batteries and buses, with voltage/current monitors with alarms on each bus. I have redundant minimum IFR instrumentation split between the buses.  My minimum "fly to an airport in hard IFR" load I calculate at 17.4A, which I can source with a worst case single point failure.

When I test fly the AC I'll test the power system, but I believe I sufficiently redundant and monitored to cover the 'possible" situations. (remember, nothing is 100%.)  BTW- one thing I do not have is an Avionics Master. It is a designed in single point failure. Just turn the units on/off individually.

Paul Bricker
N63PB