If the signs don't convince you that the US election was rigged, they shouldn't convince you of other elections being rigged, either.
(I'm not from the US and don't care much about the US election. But I do think that the comment which sadly was flagged made a valid point about the signs not being useful indicators if they also apply to elections which are not rigged.)
Where I live, no one questions that the election was rigged. Most believe it was. I haven’t done enough of my own research to know one way or the other.
The problem is that it's too easy to hallucinate new challenges. It's easy to claim some guy stuffed ballot boxes with no evidence, and if people want to believe that, they will unless given irrefutable proof to the contrary. But how do you prove irrefutably that Fidel Castro definitely did not stuff all the ballot boxes? Apparently, you can't.