Howdy everyone. Just registered on this site a few minutes ago. Have cruise with HAL twice over the last 5 years. Yes, the line caters to the older generation and on our last cruise I can honestly say that the sidewalks were pulled in after the last show - around 10:30 pm. Went to several of the bars and they were also empty. This may not be the case on our ship but be prepared just in case.
What we have seen are groups of teens getting togther at night in one of the lounges just sitting around & talking. During the day we rarely see them so there must be something for them to do. Other than that you make the cruise what you want to make it. We always find ways to have fun and keep ourselves occupied on a cruise.