For me, there's definitely a line.
If you're a guy like Granderson who *always* stands real close to the plate and you just don't shy away from a pitch that's headed at you, fair play.
The intentional leaning-in, though, seems like a bush league move to me. Danny was getting really bad with that towards the end of last season. The free base is supposed to be the pitcher's penalty for not pitching better, but a free base after intentionally leaning in is just punishing the pitcher without the pitcher actually doing anything wrong. It's like you're stealing first, but instead of stealing it on talent or penalizing someone for their mistake (dropped third strike), you're just cheating.