This isn't television, it's a movie. And many non-porn actors have had semi and erections in movies, just search through this forum for examples. Yes it can effect the films rating, but its not banned, and even if films use realistic prosthetics they are often treated the same as the real thing when it comes to ratings it if it to simulate an erection. Most famously, Michael Fassbender had a fluffed frontal scene in the film 'Shame'... so NOTHING is set in stone in terms of what can and can't be shown on screen, it's up to the actors, directors and studios and how it effects their rating. And AGAIN.. this was hardly a full on erect full frontal.. it was a barely visible, slightly larger than flaccid, kinda half side nude scene... and AGAIN I'm not saying it's not a prosthetic, but there's also no reason to believe it isn't either, especially if you consider if they were going to go to that effort, why would they have the shot like THAT and not actually make proper use of it as is usually the case in most projects, such as the examples you gave?