26.605 MHz is another popular one for Latin America, especially Mexico but I've heard Dominican Republic on the "low band" channels (26515 to 26955 kHz / 26.515 to 26.955 MHz)...often you'll hear music and noise toys playing various recordings over each other.
I remember seeing a video on YouTube a while back about a Mexican CB shop doing modifications for Cobra 29s and similar AM only rigs to give them 80 channel capability, channels 1-40 were the regular 40 CB channels, and channels 41-80 were the low band channels (skipping the "A" channels 26.545 MHz, 26.595 MHz, 26.645 MHz, 26.695 MHz and 26.745 MHz) and following the same out-of-order channel steps for channels 23, 23, 24 and 25 - so that the 80 channel rigs would "track" with export radios operating on the low band or "down one band".
Latin American truckers are just as likely if not more likely to have the capability to transmit out of band as American truckers are, and let's not forget the Mexican taxi companies using out-of-band frequencies as their own land mobile radio service for taxicab dispatch!
It is also possible that you've stumbled upon a local freeband channel, presuming that the nearby watering holes (26.565 MHz, 26.585 MHz, 26.705 MHz, etc.) were quiet but 26.605 MHz was active.