Depends on the kind of gang-tickling, too. I agree with the intimacy of 1 on 1, by the way. But some of the best tickling that I've seen has been gang-related.
Thinking back to high-school days, I can recall a few times where the lee wasn't tickled by more than one person, just restrained while each of the gang took their turns. I was even on the receiving end in elementary school one time.
I remember when I was in high-school I had a friend over and we were discussing girls in the class, and got around to one named Leslie. I mentioned her name and he just kind of shivered (seriously). I asked what was wrong with her and he said that in elementary school, she led a small gang of about 7 girls that used to tickle the crap out of him and some of the other kids. He said that they would chase him down and drag him to part of the playground where the "playground aid" didn't check often. I never went to his school, so I don't know the details. The playground at my school had no such place.
Anyway, once there, a girl would sit on each arm and the rest would stand around, and one by one they would sit on his hips and tickle him mercilessly on his upper body. He suffered this fate often (like weekly), and said sometimes he would spend an entire half-hour recess being tickled with no breaks.
I guess the point is that gang-tickling can be 1 on 1, too, but obviously there's something special about being alone with someone you love. Of course, we didn't care about that on the playground- it's a whole different world.
I wonder if Leslie's husband is a lee, too, but I'm guessing he is.