Penetration bonuses

[Ewierl]

Do "penetration bonus" items only boost penetration values for spells, or do they also increase penetration values for other MR-negating effects from various items and special abilities? For example, will a Gorgon have a higher chance of petrifying attackers if she's wielding a rune smasher?

Does anyone know the answer?

[Wish]

spells only

[Graeme Dice]

I'm almost completely certain that they only affect spells.