Romeo - 9:47 pm on Jun 3, 2005 (gmt 0)

Or whether it is in fact a tool aimed at identifying spam/scrapers in some way.

I doubt that this is behind the sitemaps.
A lot of private small sites have no capabilities of running python scripts at a shell prompt or even know about.

Just tried and submitted for one of my sites and watching the logs now what will happen then ...

Google first says something about
# Better crawl coverage
# Fresher search results
# A smarter crawl
on one page and later says
# Please note that we do not add all submitted URLs to our index, and we cannot make any predictions or guarantees about when or if they will appear.

Lets see ...

Regards,
R.