The light neutrinos are disfavored as an explanation for the observation of dark matter, due to considerations of large-scale structure formation in the early universe.
An alternative approach is electroretinography, although this is often disfavored for children, since its discomfort can also make the results unreliable.
These terms are (in descending order) purposely, knowingly, recklessly, and negligently, with a fifth state of strict liability, which is highly disfavored.