I am researching what you say now. You may be right, and if so, I'll say so. If you have any links to references that address whether weather is transmitted to non-ADS-B Out aircraft that would be helpful. So far, what I've read either glosses over the subject, or supports what I said. For instance this quote: "The system will show detailed regional radar imagery within 250NM of your current position, and is updated every 5 minutes." But I'm fully prepared to admit I my have had an incomplete understanding regarding FIS-B.
Edit: at https://www.faa.gov/nextgen/programs/adsb/pilot/ they don't say it directly, but by omission it's implied that unlike TIS-B (traffic) where you have to be a "client" by transmitting ADS-B Out, they don't say you have to be a client of any kind to receive FIS-B (weather and other information). So, I think now that you are correct and that I made an incorrect presumption that I knew more than you. I was however concerned for your safety (and anyone else relying on ADS-B In without Out), and that's where I was coming from. And in regards to traffic, what I was saying was correct.
I would still like to hear from iFly staff on my questions, when one of you gets a minute.