This is a very big problem when roaming, about 400kB are transferred on each Maps launch even when network positioning is turned off and your region maps are the latest version. This makes Maps unusable when roaming (or at least very expensive). Please vote if you are affected by this:
https://bugs.maemo.org/show_bug.cgi?id=9594

EXACT STEPS LEADING TO PROBLEM:
(Explain in detail what you do (e.g. tap on OK) and what you see (e.g. message
Connection Failed appears))
1. Download and install the latest map for your region
2. In Settings turn off Network positioning
3. Open up Maps application and wait for it to find your position

EXPECTED OUTCOME:
No data is transferred if the installed maps are the latest version and not
using network positioning.

ACTUAL OUTCOME:
There is about 400kB worth of traffic upon launch (8.5kB upload, 391.5kB
download).

REPRODUCIBILITY:
always

EXTRA SOFTWARE INSTALLED:
not applicable

OTHER COMMENTS:
This is a very big problem when using data while roaming. 400kB on each Maps
launch is pretty steep (about 2.40EUR in EU, at 0.06EUR/10kB) and makes using
the Map application impractical and very expensive.