Dashofpepper wrote:Fearless units can still be pinned (see the Deceiver's special rules). While a fearless unit cannot normally be forced into a pinning check, they weren't fearless when they were pinned - becoming fearless doesn't retroactively fix states, only prevents future ones.
Next time, if you're concerned about critical units becoming pinned when you need them, keep in mind that Ghazghkull's Waaaugh! lasts for a full game turn, not a single player turn. You can declare his Waaaugh! after taking wounds but before taking your pinning test if you like.
The Fearless
USR states that "...troops automatically pass all Morale and Pinning tests they are required to take..." It doesn't make you "immune" to being pinned, or automatically stand up from being pinned if you gain fearless (it does for units falling back that become fearless because that is specifically listed in the fearless entry).
Since the unit of boys already took their test and failed, they are pinned. They do not "snap out of it" when gaining fearless.
The Deceiver has a special rule that makes fearless units able to fail their pinning test. He's not a good example for comparison.
A better comparison would be to the space marine's "And they shall know no fear" rule with regrouping.
ATSKNF says that they automatically pass tests to regroup and can do so even if below half strength. It's still possible to run a unit of space marine's off the table by making them fall back, and then keeping an enemy unit within 6" of them. If they don't get the chance to take the test, they don't get the chance to automatically pass it.
Edit: Ninja'd by Dash's edit