We put the question mark in above. That's a standard moderation tactic we use when a headline makes a dramatic statement that we have no way of verifying.
The statement in the OP's title breaks the HN guidelines by being misleading (presenting an allegation as fact) and baity (by using sensational language like "betrayed"). Putting "Petition:" in front does mitigate that, but not enough in my view.
If anyone can suggest a better way of solving the problem in this case, we'd be happy to change the title again.
I perceive the question mark at the end of the headline to mean that A) the author believes this but doesn't want to be "on the record" for something that lacks evidence, or B) the author doesn't believe it and just wants clicks.
An imperfect solution used by newspapers is to put the source of the allegation at the beginning: "Montoya: You killed my father" or "Sources: US plans to invade Canada".
Either way, some damage will be done by false headlines. The question is just whether you can signal to HN users that the article is speculative.
Personally, I would prefer a declarative headline with a modifier like "allegedly" rather than a question mark. I also like the idea of attribution--"Fight For the Future Alleges Facebook Is Lobbying for CISA."
The statement in the OP's title breaks the HN guidelines by being misleading (presenting an allegation as fact) and baity (by using sensational language like "betrayed"). Putting "Petition:" in front does mitigate that, but not enough in my view.
If anyone can suggest a better way of solving the problem in this case, we'd be happy to change the title again.