Ratfolk + Teamwork / Rogue = Ew.

[Snickersnack]

I'd allow it in my games since it requires not only for an ally to be flanking the target with the user who has the feat, it has two feat prerequisites, and the BAB has to be +10. It also limits the flank to within 30 ft, which still puts the PC who picks up the Ranged Flank feat of being charged or bull rushed.

You can't expect a 3pp to write correct RAW. It's pretty apparent they meant to clarify flanking from range and did not consider a ratfolk's Swarming trait because it would make the feat entirely too wordy. Other than that, there could be no other misconceptions of the purpose of the feat.

[boring7]

Or they WERE aware of it, or aware of some teamwork feat that works a lot like swarming (Pack Flanking comes to mind) and worded it that way instead of "closest square for purposes of flanking." RAI is a crapshoot, especially with 3pp. And it still only works inside 30 feet, sniper goggles notwithstanding.

I mean you can rule it how you want, but no one else is bound to that or liable to let your declaration of victory go without pointing and laughing.