Not true. I used my old 3G with Navigon without a data connection, get a lock within seconds.
I now use my iP4 without a data connection and Navigon finds my location whilst indoors within seconds.
Your experience versus the original thread author could be explained at least partially by a few components of the iPhones core location service.
One component of the location system in the iPhone is cellular triangulation. Cellular triangulation does not require an active data connection but it does require a sim card because it takes advantage of signal strength and data in the GSM standard. So even without cellular data the iPhone can use this to get a rough location estimate. This differs from assisted GPS where the assisted component does require an active data connection.
Secondly, the GPS satellite constellation data and the correct time are really broken down into two parts, almanac data and the ephemeris data. Almanac data is a rough guide of the GPS constellation and is valid for days to weeks. Ephemeris is more accurate GPS constellation data and is valid for up to 2 hours in a specific location.
So if an iPhone is cold booted or its location services have not been used in a number of days the system may be able to rely on the almanac data and cellular triangulation data to get a rough position. Then it can wait to receive the latest ephemeris data for the satellites above and use this to get a more accurate position lock. But because it already has almanac and cellular data to work with the system may be able to get an accurate lock in under 12.5 minutes versus the 12.5 minutes usually required to receive all of the almanac and ephemeris data.
Both of these aspects could at least partially explain your quick time to position lock, contrast to the original thread author.
