Large controllable balloons could probably be 'recalled' by instructing them to crash into the ocean. If any more big ones like the first balloon show up, it's probably on purpose.
I was wondering why China wouldn’t include a self-destruct feature. My daughter pointed out that crashing into a US city, even unintentionally, would probably be seen as even more hostile than sending the balloon in the first place. You obviously could choose to self destruct in a remote area or over water, but they may well have considered the escalation risk to be too high if they added potentially destructive capabilities.
WSJ, linked in another comment on this post, “The craft came outfitted with small explosives to disable the surveillance equipment, an official said, though they weren’t detonated.” https://archive.is/oORem#selection-677.0-677.133
