Depends if they have some one doing the grouping. At Disney, they call it the "grouper" this is the person that says "how many in your group?" "ok, 2 here, 2 here" "how many in your group" "ok, 1 here, 2 here"...
Sea World normally does self grouping. Meaning, you pick a row you want to be in and get in line for it. And there's usually extended queues for front and back rows. Although I have seen at peak times, some one grouping at the top of the stairs, sorting out quick queue holders then standby. When there's some one doing this, they'll often times send a single rider up the QQ side.
If not, there's usually just some one standing at the bottom of the stairs sending a group of people up each side for a little more even loading. Although once in line for a row, most people in line will allow for a single rider to take an open spot. Since every one wants to go to with their group. Some times, you need to speak up if you see an open seat other times the first person will say something. And sometimes you can judge by who's talking to who, if they're a group of 2, 3, or 4.
For a first time experience, he HAS to be in the front row.