In my view, if whomever thinks the parents should be connected can't provide a reliable source of some kind, that person is wrong. I feel this way especially strongly when there are suddenly parents I've never heard of listed for an ancestor of mine that I've spent a decent amount of time looking into. That raises a red flag that there's likely some random people the right age that have been added to some Geni or Ancestry tree, and some member here is more willing to state a random guess as fact than to accept that it's unknown. Obviously revolutionary research that breaks through a long-standing brick wall does happen and is great when it does, but if I'm the one that did the research or was the first person on Wikitree to find it, I'm more excited than ever to show my work by including the sources.
If it seems reasonably likely to me that whomever connects the parents knows more than I do legitimately, or if I don't have any sense for that one way or the other, I'll usually add research notes and/or a comment requesting sources and expressing my concerns about the state of the sourcing. If that goes unanswered for a while, my assumption is that nobody is too invested in the connection, and that it likely was added just as lightly.
I killed my alleged blood connection to Bill Clinton a week or two ago on that kind of basis. Parents with no sourcing were added to my ancestor Exolheath Page, despite none being proposed in a very thorough book that was written about his family a couple decades ago. As far as I could tell, they were added because they had the same last name, had reasonable birth years to be his parents, and lived in the colony of Virginia, as did he.
