Yes. Other passengers using walkies talkies may tune into your channel unknowingly. In that situation, you may switch channels to limit interruption. An easy to prevent this from happening is to look for radios with extensive frequencies.
Another handy feature in most modern walkie talkies is privacy codes. It doesn’t secure your communication but instead limits the noise. However, keep in mind that having a privacy code doesn’t stop others from accidentally listening to you and your mate talking.