I think that's untrue, just because it has a variable fuse doesn't mean they don't know how long it is.

For example, one grenade has a fuse of 15 seconds, another has a fuse for 13 seconds. Someone wouldn't hold it for 12 seconds, they would hold it for 5 maybe 7 seconds and then throw it.

Agreed, in Arma 2 it was a hassle to do so, but now it's just impossible.

ShackTactical's video showing the grenade mod would be fantastic.