How about the FizzBuzz Principle?
If someone is making a claim that contains egregious, deal-breaking errors and falsehoods that you are easily able to fact-check, you can safely assume that the aspects of their claim that are above your pay grade will not be any better.
Named after a coding test, based on a children’s game, that is commonly given to candidates for software development jobs at a very early stage in the process to allow the recruiter to short-circuit the interview process at the initial phone screen and spare the company the expense of an on-site interview. The idea is that if they can’t handle the easy stuff then there’s no point in wasting time on the more difficult stuff.
In the context of checking claims about science, you can look for things such as claims that can be falsified with nothing more than a back-of-the-envelope calculation with only high school maths, or that can be falsified with nothing more than a quick Google search on your mobile phone, while they are speaking.