If I double a bread recipe do I double the salt? I think it was my mom who gave me the rule of thumb that when you double a recipe you double everything except the salt. 
I'm willing to defer to her wisdom for the sorts of soups and stews she liked to make, but she didn't do much baking, and I never saw her make bread leavened with yeast. 
I know salt and yeast aren't friends and I'm trying to double a rustic ciabatta recipe.
If you’re measuring your ingredients by weight, I don’t see any reason not to double the salt. I usually do. If you’re measuring ingredients by volume, it might be best to err on the less salty side, as different types of salt have different densities. Hope this helps