I HATED the way that Harry found out about Sirius (in the pub) - When reading that part in the books, it really grabbed a hold of me, JKR wrote it in a way that made you feel what Harry was feeling.
Same with the Shrieking Shack scene, It was meant to be emotionally charged and have you on the edge of your seat trying to find out what was going on.
But no, there was none of that.... just a gay Lupin and a Sirius with stick on tattoos! (and Peter.... Ewwwww!)
I didnt see the tattoos on McNair BUT doesnt the dark mark not show until Voldemort summons them? otherwise they would be showing off their allegiance to Voldy.
Wasnt McNair one of the ones who swore he wasnt a deatheater? If the mark was visible all the time, then it would be obvious he was....
But then again, in the movie anything is possible - it was all wrong!!
"Now Now Draco... Play nicely"
Harry Potter and the Chamber of Secrets