The following is an answer and/or comment by inhahe aka ColorStorm (inhahe.com - myriachromat.wordpress.com).
Someone else:
1. Extraordinary claims require extraordinary evidence. 2. If two competing theories offer the same confirmed experimental predictions but one makes extraordinary claims, that theory should be rejected unless extraordinary evidence is presented in its favour. 3. This is a parsimonious choice, a correct application of Occam's Razor.
A quantum interpretation positing that physical systems don't exist until they're observed should be rejected in favour of any one that doesn't make such claims, unless extraordinary evidence is presented that such a miracle actually occurs.

Me:
The problem with this logic is that not all claims are physical theories. Occam's razor applies best to physical theories. Outside of that realm, other factors impinging on the likelihood of the "claim" or outlook or whatever being true apply than merely the evidence that is both easily analytically accounted for and indisputable.
For example, someone's idea that quantum physics should be interpreted to mean that physical systems don't exist until they're observed could be influenced by his mystical or spiritual outlook and beliefs, which in turn could be the result of his entire life process: everything he's even read and carefully weighed, thought, imagined, realized, heard, personally experienced, etc.
And secondly, how extraordinary a claim appears to be is relative to the observer, because it's entirely dependent on one's fundamental worldview/outlook. For example, to the spiritualist/mystic I mentioned above, the claim that physical systems don't exist until they're observed may not be extraordinary at all. And sometimes an explanation or theory that one sees as extraordinary, another person sees as intuitively more obvious or likely than the reaching assumptions the other makes about how things could work in order for the phenomenon in question to fit into their worldview.
Take, for example, someone attributing some observed form of telepathy to the brain unconsciously taking in subtle sensory input and calculating what it must mean about what another is thinking...depending on the exact situation, this may be more outlandish and presumptuous than simply assuming that telepathy is a magical energy exchange between incorporeal minds, to someone who's fundamentally open to such ideas and outlook.