It really depends on what the battery did to the rest of the device. Apple won't decline replacement simply on the basis that it might happen again. Battery swelling tends to happen for rather random reasons, including possibly power management or due to something that happened randomly during manufacturing.
The big thing Apple won't do is replace a battery if there's an issue that prevents proper reassembly of the device. If the swelling bends the frame or damages the internals, Apple's only remedy for that would be to do a complete replacement. The way I've seen most battery swelling, it's usually not discovered until it's already starting to push out the display and has damaged something else.
I suppose there might be a chance that Apple may consider it OK other than the swelling battery.
Now if you're going to "local repairers" who are third-party, then I suppose they might have different standards for what they consider worth of repairing.