The disclaimer posted on the Wiki is derived from legal opinion based upon American copyright law in order to protect IPACS from any user misuse. If you choose to share any sceneries made using FSET, that's fine, as IPACS has only released a tool to convert aerial imagery from ANY origin into Aerofly FS2.
USGS imagery is 100% public domain. Crediting them is all you need.. I'd imagine the geological surveys of other countries have similar usage requirements..
