The methodology:
A single plot beacon (two plots tall to make sure it’s a part of settlement), 10k prestige by itself, by a character that only has this beacon in the settlement. The settlement is a hamlet. So, beacon should generate 30c per character once per cooldown period.
Once a day the beacon owner checks the footfall, then Test Character A (different account, has a beacon in the settlement) crosses that beacon, beacon owner then verifies if footfall changed (so far in the past seven days, only once).
Then test character B (no permissions or beacons on the settlement, same account as Test Character A) steps into the beacon. Owner checks footfall again. So far in the past seven days, this character generated footfall twice.
Edit: Test has been going since last tuesday, which was the first time in the past seven days that had footfall generated by both test characters. Second character generated footfall again thursday, and nothing since.
I’ll keep testing daily in the hopes of figuring out the ‘new’ cooldown, assuming that it’s predictable instead of random. Maybe it’s once a week now. 
Edit 2: Further clarification, both test characters are not in the friends list of the beacon owner, or of any character in that same account. It’s doubtful that this would have an impact, but they were removed from friends list before the test beacon was setup, just to be double sure. It’s always good practice to eliminate variables when doing science. 
The removal was mutual: no characters from either account have any characters from the other account in their friends list.