1. Sources are often arguable if they are legit or accurate.
2. Elections are time sensitive. Ya only need to freeze a story temporarily to make it not worth anything regardless if it was accurate or not.
3. They would abuse it. It would do more harm than good.
There's a very easy way to make something unarguably true (stuff you learn in middle school, really...), don't say "this happened", say "source A states that this happened". If you have interpretation to add, "I believe that we can conclude this."
That's a habit all media sources should be taking, regardless.
Bet with PeH:
I win if Arms sells over 700 000 units worldwide by the end of 2017.
Bet with WagnerPaiva:
I win if Emmanuel Macron wins the french presidential election May 7th 2017.