One wonders about Klaestron ability to deal with disgruntled neighbors. The ship that Tandro used presumably wasn't overtly Klaestron, or at least there would be little reason for it to be if Tandro could arrange for a bit of anonymity instead. Him being able to secure what looks like Talarian military tech might establish the Klaestron have access to weapons that have been previously explicitly used to challenge the Federation - boding ill for bit players like Bajor. Then again, special forces are hardly representative of regular forces, and a one-off criminal operation may be the only type for which Tandro could purchase, rent, steal or otherwise acquire such a vessel.
Possibly Starfleet would have made short work of "allies of Cardassia" in the recent war, in order to render the surrounding space "neutral" rather than still overtly allied with Cardassia. But the one-way extradition treaty smacks of appeasement, perhaps because Starfleet never had the time or patience to do anything about Klaestron bullying and posturing. Or then the treaty exists because the Klaestron are known to be utterly harmless?
Timo Saloniemi