They were having a blast running around chasing each other.
Yes, Benjamin's shirt is backwards. Most day's you will find either 1 or 2 articles of clothing backwards on Benjamin. It's his thing - he likes it and I just don't feel inclined to make a big deal out of it. The great part is that he dresses himself every day, so who am I to complain.
Funny side note: I would have NEVER let Jack go out with backwards clothes on. It's funny how your perception of what's really important changes the more kids you have. Makes me wonder what Annabelle is going to get away with :-)