I think Gary's skepticism of the high odds against reception are totally valid. The alternate explanation, though, really doesn't make any better sense. As someone else pointed out -- and again we're back to the issue I keep bringing up about coming up with counter theories where we try to make optimal things happen without thinking through the scenario within the limitations of the actual situations at hand (something that, again, I have found TIGHAR rarely guilty of) -- it was not that easy to make a bunch of sound clips and arrange them in such a way that it would sound like a host broadcast. In fact, it would be nearly impossible. Forget digital recording...tape itself was not invented until World War II. (On the topic of sound, I can claim some expertise) If I was going to try to do such a thing with 1930s technology...well, I imagine it would be within the capability of sound and movie professionals, but not too many others. And why?
But the main issue with the hoax theory is
1. why did no one else hear it? Even if it was a War of the Worlds kind of a thing, a lot of people were freaked out by WOTW. It beggars belief that someone mounted such a hoax and only one person heard it and commented on it/were fooled by it; and
2. why were the messages themselves so garbled if it was a hoax? I think it's significant that all of the known hoaxes contain semi-clear information that any person could dream up, and the possible post-loss messages don't. Again, I submit that this is much more in line with how the real world works. If you're a hoaxer, you broadcast what people expect you to broadcast. But if you're hearing a crummy signal that's fading in and out and threes sound like Z's and fun sounds like 1, you're going to get a transcription that looks exactly like Betty's Notebook. And if the people on land didn't know exactly where they were and, for example, their plane was going over, then something like that might conceivably get broadcast. As unlikely as that might be, I find it more unlikely a hoaxer would dream that particular scenario up and broadcast a bunch of random numbers and letters.
Gary has rightly stated that the odds of receiving the message were on par with winning the lottery. Very fair statement. But I do want to point out that...people do win the lottery! And that's because there are a lot of people buying lottery tickets. Gary has asked how many people were listening on the radio at the time, and I would say that, as it was at that time the primary form of mass communication, the answer is, a hell of a lot, more than we can conceive of now. So yes, the chances of that one person hearing that one transmission is pretty unlikely. But so are the odds of a lot of things if conceived that way....one in a million occurrences happen to most of us each and every day. When considered in isolation, they are miracles. Taken together, it all evens out as just the random skein of God's day-to-day creation.
So do I have a problem believing someone on a Pacific Island sent out a message to the world, and of the whole world one random teenager in Florida stumbled across parts of it? Frankly, no I don't. Because, as is the case with so many other parts of the TIGHAR saga, I find the alternative explanations objectively less convincing. And weird stuff happens all the time. What are the chances another family with the unusual surname of Marsland booked a room at the same hotel the same day my band dropped in to town to play a gig, causing great confusion when we all tried to check in? Pretty low, but it happened to me in 1997. Unlikely stuff happens, and if a statistician calculated the odds of it happening on that particular day it would be astronomically small.
To me, the only two plausible scenarios are either she heard what she heard, or Malcolm is right -- she made up the whole thing.