The second is also implied by the first, if "primes more often than non-primes" means "out of proportion with how many primes there are" rather than "more than 50% of the time", and I think it would be equally interesting to look at whether [odd] primes are more likely to be chosen than odd non-primes.

I wonder if the real issue is "that the person can/can't recall (part of) the factorization offhand" - that would make sense if people avoid numbers that "feel round" - something with an obscure factorization like 51 [3*17] might be more likely to be chosen than even numbers, multiples of 11, numbers that appear on a multiplication table (so, 3 times numbers 10 or less).