This is more of a feature request. 
All my designs are usually narrower than what the full width of the site allows. Sometimes it is 1100px, sometimes 1000px and so on. I could define the max site width, but then I’d lose those situations when I do need wider sections.
for that reason, I usually write a CSS class that narrows the Row, or I turn the Global container off, set the max size and then turn the paddings on to account for mobile edges.
I know gutters (used on Bars) are basically the replacement for paddings, and if they were added to Rows, we’d get double functionality. But still, Setting those paddings when turning the Global container off is so common, that I believe this would be justified. I’d love to see the Gutter option with the initial value of 2em inside the Size group when the Global Container is turned off.