I have found a funny behaviour of geo-newest
Look at this:

$ geo-newest -r 100km -n 100 -I unfound -s sweden N63 E17
BayofOmne 62.96145 18.39080 Geocache-unfound-regular
AngeCampingPonderosa 62.51645 15.61790 Geocache-unfound-regular

But

$ geo-newest -r 100km -I unfound -s sweden N63 E17
<nothing>

Meaning I need to put a high number to the -n option to make it work together with the -r option.

@Karro:
Apparently the -n setting precedes the -r selection - in a way that a maximum of "newest" entries is fetched from the server *for the location selection*, before other selection criteria are applied (at least the -r one; perhaps the -l one as well). The source (geo-newest.sh) suggests this, too.
The default for n is 20 - but even with 100 you only got two lines of output.
It seems to be a matter of bandwidth-saving, and therefore a feature...