It seems like it's at the same level of the rule that the pilot and co-pilot can't order the same meal at the airport before a flight in case they both get food

It seems like it's at the same level of the rule that the pilot and co-pilot can't order the same meal at the airport before a flight in case they both get food poisoning simultaneously. Doesn't guarantee that they don't both get sick, but it's a relatively minor imposition and reduces the odds by quite a bit.