this "study" is going to have a lot of flaws and really there's no sense in looking too far into it as it's simply a shitty fuel pump.
im expect to have skewed results because i would assume most people that have 335's have a garage to park their car in.
now if you rephrased the question and make everyone answer regardless of whether their fuel pump failed you might have more conclusive results.
but then again people with broken fuel pumps will probably be more inclined to respond.
doesn't change the fact that the fuel pump is a problem and no matter what should not break if you park outside at night