I don't think it's a lie either, just trying not to completely rule out what the OP was saying, but the lazy or irresponsible thing would be not to do anything. This promise to give a message through the service, because you won't be near a phone, is kind of sad in its maybe doomed effort not to fall out of touch.
I used to say the new line should be
I'll call you in the morning if there's service on the train...(Or plane...Do people actually use onboard phones in flight? I know you can't use your own...)
Maybe better would be,
I'll call you in the morning or my intern will explain...
