It sounds to me like even when it's the fstrim utility, which uses some ioctl() to tell the kernel to trim free regions in a range on a filesystem, the kernel ends up causing the queued trim command to be used if available.

The "blacklist" does not appear to have any constant to blacklist old-style trim, only NCQ_TRIM (and other odd stuff, most notably all NCQ usage).

This makes sense, because if some SSD advertised old-style trim but was corrupted by it, then it would be found and fixed sooner by these vendors, because Windows 7 would exhibit the corruption.

I see the addendum to your post; touche, I guess these drives do indeed lack queued trim, and have some issue with plain old trim. That's rather surprising, to me... I was going to say "especially for an enterprise-grade drive" but I'm not so sure...