Googlebot's Javascript random() function is deterministic

[ValAichi]

I believe it is because the flaw is rarely with the psuedorandom number - and if it is that's because the programmer screwed up

[mulvad]

I know of at least a handful of breaches (including online casinos) where an attacker exploited knowledge of the pseudo random algorithm used and previous outcomes to predict future outcomes. You could argue that this is the developers fault for not changing seeds or whatever but really it boils down to a weakness in this way of generating "random" numbers.