Most human beings in any forum, anywhere, will be more obsessed with signaling and other concerns than The Truth -- even in a pseudo-anonymous survey -- and will be subject to most of the standard cognitive biases that bodybuilders will be, even if to a lesser degree. Being obsessed with The Truth does not mean never lying or exaggerating (or reporting just that one internet IQ test you took that was 1 std dev higher than your real-world test).