I always thought when we use the dependent clause after the main clause, we don't need a comma before the subordinating conjunction for example,
I always sneaked into the movies to see an R-rated although my parents never would've approved.
till I came across this sentence,
The website says it's because the information remains true, no matter what you add in the subordinate clause.
I seem to fail to understand how you can add some information that make the comma unnecessary. Interestingly the same is true with although.
He kept charging to his card, although his account was overdrawn.
How can I add some information that can change the main clause! Should I say something like,
He kept charging to his card although he didn't!
I don't think so. So what's the trick? What's the point that I'm missing?