According to toller :

Most zaps from a 240V circuit will be 120V from hot-to-ground. Even if
you hit hot-to-hot, you're likely to have _some_ additional leakage
to ground too. As such, a GFCI _would_ work.

Have you actually tried this, or are you just guessing?

Think about it: for every time you touch the hot wire of a 120V circuit,
how many times would you conduct enough current to, say, the floor
you're standing on, to trip a GFCI?

Most times.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.