Fil-ams didn't do research :CAVITE IS NOT A PLACE FOR ABU SAYAFS
Obviously a film written with stereotypical perceptions of the Philippines by American born "flips". Did they even do a little bit of research?
The concept of Abus running large in Cavite so absurd and so fantastical that it already destroys the suspension of disbelief before even watching this film. Everyone in the Philippines knows there are no Abu Sayafs in Cavite.
Well it's not exactly the best place to do their operations because it's so geographically wrong for their kind of business. Most of the province is flat, contrary to the fact that the terrorists prefer the mountainous forest regions of the Philippines for guerilla tactics. There are also only a few ways to go in and out of Cavite: Going via the sea is out of the question as it lies just beside Manila Bay and can be easily monitored by the Sangley Point Naval Base. Via the road is also harder as the highway goes exactly straight to Manila with all the checkpoints and highway patrols.
So basically, the Abus can't easily run and hide in Cavite. That's why they dwell somewhere else.