Not entirely true as anyone can legally transmit on ham bands in the event of an emergency.
[...]
Even if you don't plan on getting your ham license you can use it during an emergency.
Here's a pedantic legal "by the book" clarification i'd like to make, because because it's an important distinction: You absolutely cannot transmit while unlicensed in an emergency unless it is necessary for the immediate safety of human life
Subpart E—Providing Emergency Communications
...
§97.403 Safety of life and protection of property. No provision of these rules prevents the use by an amateur station of any means of radiocommunication at its disposal to provide essential communication needs in connection with the immediate safety of human life and immediate protection of property when normal communication systems are not available.
So, for example:
Vehicle broke down in the middle of the desert? NOPE. Can't transmit.
Vehicle broke down in the middle of the desert but you have movie plans with the wife tonight? NOPE. Can't transmit.
Vehicle broke down in the middle of the desert and you ran out of water trying to hike back, you are still a significant distance away from civilization and you still have no cell signal? YEP. You can probably transmit.
Okay, enough of the pedantic legal stuff. I know almost every unlicensed person who reads that is probably saying to themselves "Well, who's gonna know/care?" or "I'd rather beg for forgiveness than ask for permission."
I'll point back to the great practical reason for getting licensed that
@Flyte74 mentioned: Do you really want to be in a life or death situation, crushed by the stress of the situation and then trying to figure out how to properly use your radio to make a contact? At the very beginning of the FCC part 97 regulations is the section that describes the purpose of the amateur radio service. Five points are listed, and of those, the first four basically boil down to making sure U.S. citizens have a way to teach, learn and practice using radios, notably for the purpose of communication during an emergency.
NOTE: This comment is only about legality here in the U.S.A.
Edit: whoops, I just realized that section of the regs still pertains to amateur operators (licensed folks), but the gist is the same for unlicensed. I'm looking but I believe somewhere in the regs it also states the same about unlicensed operators.