Yes, I really hate that FUD. It makes people decide to use less safe filesystem because they don't have ECC RAM thinking ZFS somehow will corrupt their data, when in reality ZFS is still safe (and safer than other filesystems). ZFS claims to keep your data safe, but it can't prevent data being corrupted in RAM. If your RAM is corrupted your data might be as well no matter what filesystem you use. ECC RAM makes sure that memory is also safe and that ZFS can deliver its promises.