Looking at the situation at first glance, and even looking a little deeper, it seems like a lawsuit is certainly in order involving country singer Luke Bryan. The man in the front row was already taking an aggressive disposition towards Bryan (by gesturing his middle finger at the singer). After being assaulted, I assume he now feels even more aggressive. When a famous person attacks you, it's typically an excellent time for a law suit. Famous people typically have excess money, and are able to make a settlement quite easily without much financial burden, often without even going to court. I assume a law suit will certainly happen, and if not a full law suit, then an out of court settlement. There is plently of evidence from the cell phones that were inevitably filming during the incident at this concert.
Caught on tape= slam dunk for even the worst attorney in the business. It doesn't matter whether or not there are injuries sustained. It's against the law for you to put your hands on another person in a violent manner.
The guy who got slapped can laugh all the way to the bank.
Yes, the concert goer that Luke Bryan hit will sue the Country Star because there is no reason for the singer to have hit him. The person paid good money to see a show and ended up getting smacked. That is wrong. It is not Luke Bryan's job to discipline his fans.
Most people would sue after being struck by someone famous. Because this happened during a concert, there would be witnesses, which means that Luke Bryan's lawyers would want to give the concert goer a quick settlement to get this unfortunate incident behind them. Settlements like that are almost always a way for some quick money, especially with witnesses, so the majority would end up suing Luke.
If Luke Bryant takes care of any injuries the concert goer had, and he appologizes, the fan probably will not sue. Of course it is hard to tell what will happen in a case like this, and it depends on why he hit the fan and if there were any injuries.