I want to preface this article by saying that I know there are more secure, reasonably priced radios available, such as the frequency-hopping XFS systems, but I want to drill into FRS Radios for this post.
I’ve read many articles, watched many videos and spoke with quite a few folks regarding sustainable communications in bad times, there is a common belief that FRS radios are ideal for dependable(?) short range communications, using tools that do not require a degree in electrical engineering.

I agree, to a point. I believe that FRS radios offer very INSECURE semi-dependable short range communications.
I’d like to address a misconception that many people believe secure comms via FRS can be attained by using what are often called group codes or sub-channels, sub-channels are actually CTCSS encoding/decoding. CTCSS or “Continuous Tone Coded Squelch System”, is a method that transmits a sub-tone given frequency when you transmit, that tone is received by all FRS radios that are on the same sub-channel, this tone breaks the squelch on those radios, and passes the voice traffic.
Lets break that down:

1. Group 1 decides to use FRS Channel 1 and sub-channel 5 for patrol communications.
2. Group 2 chooses FRS Channel 1 and sub-channel 2 for emergency communications.
3. Each group will be communicating with a HQ radio tuned to the correct FRS channel, and sub-channel.

Okay, now lets see how this all works:

1. Group 1 reaches a checkpoint, and radios back to base that they have arrived, and have nothing to report.
2. This takes place on FRS Channel 1 and sub-channel 5, the patrol base radio receives the subtone for sub-channel 5, breaks squelch, and the patrol traffic is passed.
3. The base radio for emergency communications is tuned to the same FRS channel (channel 1) but is NOT on the same sub-channel, so squelch is not broken, and the traffic is never heard.
4. An emergency message is sent from a vehicle in Group 2, and like in step 2 above, FRS Channel 1 is being used, this time with a different sub-channel. The base radio emergency traffic received the subtone and the traffic is passed.
5. The patrol base radio, and the patrol in Group 1 are NOT on the same sub-channel as emergency, and they never hear the traffic.

Now this all seems like a decent system for secure comms, but here’s the kicker. If you do NOT enable a sub-channel on your FRS radio, you hear all traffic on the given channel.
So, in the above example, if a stranger had his FRS radio tuned to FRS Channel 1, and no sub-channel, he would hear (assuming he was close enough to receive the transmissions.) the patrol check in, and the emergency message.
FRS is -NOT- secure
However, just because FRS isn’t secure, doesn’t mean there isn’t a place for it, and while I won’t say I have a ‘secure’ solution with FRS, I have an option that will make your FRS communications a bit more secure.
Remember, there are millions of these radios out there in the world, FRS Radios are like AK’s, you can find them all over.  These are the radios that most people will have if they have any  radios, you may want to monitor that traffic, you may want to reach out to others, so having FRS radios is part of my comms plan, it should be part of yours as well. If you are forced to limit your radio equipment, and don’t have the option of more secure comms, I highly recommend the ICOM IC-4088A FRS Radio.  I’ve had mine for over 10 years now, and it’s still functioning perfectly. Why the IC-4088A? Simple: It has a voice scrambler function.  When enabled, only other IC-4088A radios will be able to unscramble the traffic. You’re thinking ‘Great! Secure FRS Comms!’ sorry, not quite. There is no capability to create a specific scramble type algorithm, so anybody with an ICOM IC-4088A will be able to listen in on your ‘secure, scrambled FRS comms’. I say this type of FRS comms is ‘a bit more secure’ because this is not  a common FRS radio, it is considerably more expensive (currently $100-$125 each) than the \$15/pair FRS radios you can get everywhere. If you have a limited comms capability, if you have to stick with FRS for all your comms, then seriously consider complimenting that FRS footprint with as many IC-4088A’s as you can comfortably afford.

As of this posting, you can find these radios at this amazon.com link.