and for the downside....

For the second time on FamilySearch the same person has (re)merged my paternal grandfather with his namesake born in the same month and year, despite my collaborative note - which is now yet more detailed as to why NOT to merge them.

They were born a fortnight apart, one registered in Oamaru, the other in Palmerston North, ie separate islands of New Zealand.
The separate NZ Historical BDM index entries show their different parents had been added to a note on each, but that didn't deter this person.
Yes on the surface it looks like the one who married first may have moved islands and remarried but he didn't. He remarried a bit further north.
It doesn't help that the older fiche birth indexes for New Zealand don't make it easy to find them to add the place details to the exact birth dates and parents available from the Historical BDM index online at the Dept of Internal Affairs.
Both are indexed as Archifold Hinderson instead of Archibald Henderson!

This time I've added yet more research into the note on both profiles.
The North Islander has been placed safely up in Te Kuiti with his 2nd wife in the 1919 electoral roll, his father's obit has been added  as well, which places him in Cambridge (Waikato, North Island) whilst my granddad is recorded down in Woodhaugh, Dunedin in 1919 with his first and only wife Agnes later moving to Roxburgh, Otago (South Island).
I do know that he once ventured north, at least as far as Wellington, on his honeymoon, but he did not already have a son by then, at least not Cyril.

I've also sent the chap a message via FamilySearch to PLEASE STOP merging these Archibalds.

WikiTree has also been updated with a disambiguation note on Granddad, with the other chap now also added there, he is after all nearly family - his son married my mother's 2nd cousin!
But there are other things I'd rather have been researching last night in the time spent doing the additional research that should, hopefully STOP the "helpful" person from merging them again.

Thankfully such persistance is rare, and an apology has just been received.

This does not detract from the overall benefit of sharing tree research.
We do not own our ancestors but we do owe it to them to be remembered accurately.

Such trees do tend to get better over time as duplications are reduced, research notes added etc.

Just the other day I was re-examining the scant tree of a DNA match on Ancestry wondering where his missing link to my DAWE family was and this time round, someone had added exactly the link I was missing.
The FamilySearch tree has now been extended to link him back to the rest of his ancestors already there.
This allowed me to breakthrough that mystery and connect in a newfound 3rd cousin thanks to both DNA and the collaborative tree at FamilySearch.

So mark your key people to be "Watched" so you can keep an eye on changes, you never know what you will learn, or who you will "meet" as a result.