Sounds like the setup for some wacky sitcom hijinks.
Marc is from Belgium, Emma is from France. When it came time to decide where to live, they couldn't come to an agreement so compromised and live on the border. But what they didn't know is that neither of them ever truly gave up the fight. Tune in for their late night heists and hijinks as they try to move into their preferred country... by moving the border! Fridays at 8pm on the WEB.
Couldn't that risk cutting an ambiguous divot unmoored from either region? Might not be safe to step into such a zone once it developed. Could drift away into a different set of dimensions.