How many "ands" should a theoretical security threat have before you should just ignore the guy proposing it? E.g. If mercury is in retrograde and the stars a

How many "ands" should a theoretical security threat have before you should just ignore the guy proposing it? E.g. If mercury is in retrograde and the stars are aligned and it's Tuesday and the hacker is in position with Wireshark running on windows XP with a tethered pine phone, and we accidentally open all our ports, then we're completely vulnerable --> Ignore that guy.