Aw, this is cute. I can imagine their conversation. "It's getting late, Marisa. We should really get you home. "No! One more run, Kourin!" "Come now, you're only going to hurt yourself at this rate." "But I gotta catch up to Reimu!" "...Fine, one more run. But this is the last one!"
Rinnosuke has been watching over her for her entire life. Since he's so patient he WOULD accept all of her brash decisions and just help her out when it goes south.