you can also use the "update-title" software to regularly change your metadata (with numbers for shouts or other messages); this can fox streamrippers by splitting up their audio files as they often use metadata changes to split them into individual tracks.
http://utils.magic-radio.net/UpdateTitle2-9.zip
(the docs are in French but its not that difficult to work out).
that said I've monitored a few of them and even geolocated some [who all appeared to be from border areas of NL and DE] it turned out they were not doing it maliciously; but with a genuine intention to listen to the music at a later time or perhaps whilst walking or cycling in these areas; as if you use a mobile connection you might end up roaming between NL and DE and stung for many Euros!
for older generations many do not realise it is different from connecting a cassette recorder or minidisc to a Band II receiver (where it doesn't cost the broadcaster any more) and younger folk are used to getting "everything for free" and less aware of resource limitations.
on the Dutch pirate station relays they positively encourage stream rippers and then upload gigabytes of the broadcasts online!
Ironically the practice of playing single unmixed tracks with synchronised metadata that "copyright feds" tend to encourage makes this worse as it means there is more value to streamrippers trying to get individual tracks.