Hi Hal,
I think you may be misunderstanding how WikiTree works.
Adopting a profile does nothing other than make you the Profile Manager of that profile. There is no "Merging into your tree." WikiTree is a single family tree. One profile for each person for all users. Are relationship to that person is based on our position from our branch of the tree.
I adopt all orphaned profiles who are in my direct line or are great aunts and uncles. I do so mainly because it helps me track changes in my branch of the tree.
I will also temporarily adopt profiles for projects I am working on if they have been abandoned. Once I am done with them, I re-orphan them. It is ok if a profile is orphaned. It just means no one has taken on the resposiblity to manage that profile, rather they are leaving the profile to the community to manage.
Now, if you want to orphan a profile it is easy. Just go to the Privacy tab, scoll down to the Trusted list and look for the REMOVE YOURSELF button. Click it. Done.
If you want to do this in Bulk, and get rid of a bunch all at once, go to the Bulk Watchlist/Trusted List Changes page.
From your profile, click on the Watchlist link under the My WikiTree tab at the top of your profile. Then, from that page, look to the upper right of the page for Watchlist Changes and click on that tab. Read through the page and chose the appropriate action.
Good luck, let us know how it goes.