Every scene in a good series has to have a connection to something, nothing happens without a reason, even if the reason is not seen or understood the moment the scene happens. There are a few scenes in Digimon Tamers that don't seem to have any other reason to be there but to "comment" the relationship between Rika and Ryo or whatever this relationship means for them.
EPISODE 29, Here is the Ghost Castle! The Great Escape of Stray Culumon
Cyberdramon defeats Majiramon and Ryo knows it's time to say goodbye to other Tamers and continue his journey alone. After saying goodbye he asks Takato to say hi to (wild cat) Rika for him. Takato agrees to do it but looks completly confused by Ryo's request.
What Takato thinks of this request is not important to the story but his confusion does emphisize the importance of Ryo's words. I think this scene is setting the ground for Ryo's relationship towards Rika, his first display of affection (by teasing her if you want - he must had known that his hello was going to annoy her like he himself did when they were first introduced a day before. I think this scene is letting us know that they will have some kind of a relationship in future.
EPISODE 41, The Return to the Real World!
After boarding the arc that would get them out of the DigiWorld, Ryo comments 1) that he can finally go home (German/Jpn) / 2) asks Rika what he would get for saving her life twice (dub) and Rika responds by poking his cheek and saying something witty that makes them both laugh. While they're laughing the camera shows Henry smiling at them. He's obviously listening to them and what he hears and sees makes him smile.
I think this scene was showing us that Henry noticed Rika's walls coming down and is happy that she could be this relaxed and playful around other people.
EPISODE 51, The Power to Dream is Our Future
Tamers are fighting several D-Reaper agents, Sakuyamon and Justimon unsuccessfully the powerful Reaper. Ryo and Justimon come up with a risky plan to destroy it and ask Sakuyamon to lend them all her power to get strong enough to kill it. Rika is shocked by the plan and doesn't want to do it at first but Ryo convinces her. Sakuyamon gives Justimon all her powers, they both survive, and Justimon attacks the Reaper with his new sword, cutting it in half. However!, this does not kill the enemy, the Reaper just glues itself back together in one piece and before he has a chance to strike back, he's dragged back to the DigiWorld by the Sovereigns.
Ryo and Justimon almost kill themselves and strip Sakuyamon of all her power for basically nothing. The storyline wouldn't change much if they skipped this scene, therefore there must be another reason for its existence. I think this scene is the most important indicator on how Rika has grown through the series and is therefore willing to give all her powers to one of her biggest "opponents", if I may say so, to do what's right and save the world. I'll talk more about this here. Of course this was also one of the sweetest Ryuki moments and you could argue that displaying Rika's character development would still be possible in a less Ryuki way!