There was a conspiracy that the original titanic going down was an insurance scam.
There’s also a conspiracy that my farts smell like rancid carrots because the government puts carrots up my butt while I’m sleeping
An easily disproved one too, as the sister ships weren’t actually identical. Also the recent scan on the ship revealed the hull number 401 on one of the propellers putting another nail in the coffin of the idea the ship is actually the Olympic.