It was usually assumed that a perfect reflection of a system would have the same outcome. It's called P-symmetry, and it was accepted as fact for a while.
In 1956, the Wu experiment overturned this notion. Despite its near-maximal rejection of P-symmetry, the results were heavily doubted and it wasn't until a year later when it was repeated many times by many others that it was actually accepted.
And yet the Bedford level experiment, which has been criticized for not accounting for a well-understood effect, has been reproduced with contradictory results, and has only been reproduced affirmatively by one other, is supposed to irrefutably prove the world is flat? I think not.