I agree with all of this. My children are still young (6 & 2), but there will definitely come a time when they are old enough to go on rides without an adult and want to ride every ride that makes mommy nauseous multiple times in a row. (I suffered through Tower of Terror once for my DD6 this year. Next time, she's on her own.) I hope I can raise them to be confident & responsible enough to wait in line and ride a ride without a parent when this time comes.
Yes, exactly! Our son couldn't wait to turn 7 so he could ride Goofy's Sky School at DCA using single rider (cause one ride a day on that is more than enough for me lol.) Our first trip up to DLR after his birthday he marched straight to the ride and off he went (obviously we had discussions about it beforehand.) Yes, I admit I was a little nervous and waited where you can see the exiting riders walk down the stairs, anxiously watching to see him come down. But there he came, perfectly fine, grinning ear to ear. And since he used single rider, he was the +1 and did sit next to an adult. Frankly I was anxious about him being on a roller coaster alone, not him being seated next to a stranger.

So very sad.