I never said they had to tell the Federation the truth, but if they did ask the Federation permission to traverse their space, and didn't convince starfleet as to the reason why, I would have sent a ship to investigate the region myself. The Son'a where after all suspected to be supplying Ketracel White to the Dominion.
For all the Federation knew is that the resources to create white could be found on this planet. It would have been prudent for starfleet to survey the region.
er, I guess I don't understand your point. So the Federation finds out what they're doing.
OK, so what? It still either comes down to a PD issue or it's Federation territory. Either way, how does it affect things if the Federation investigates?