A seventeen year old with raging hormones is sent by his Rav on a tiyul with girls.
A wonder.
I am a 51 year old grandfather and I wouldn't go on a tiyul with girls. It is not a question of whether anyone will "do" an aveirah. The entire gathering is the opposite of Kedusha.
הוו פרושים מן העריות ומן העברה (ויקרא רבה) שכל מקום שאתה מוצא גדר ערוה אתה מוצא קדושה [רש"י ריש קדושים]
And then there is the gemara [Succah 52a]:
כִּי הָא דְּאַבָּיֵי שַׁמְעֵיהּ לְהָהוּא גַּבְרָא דְּקָאָמַר לְהַהִיא אִתְּתָא: נַקְדֵּים וְנֵיזִיל בְּאוֹרְחָא. אֲמַר: אֵיזִיל אַפְרְשִׁינְהוּ מֵאִיסּוּרָא. אֲזַל בָּתְרַיְיהוּ תְּלָתָא פַּרְסֵי בְּאַגְמָא. כִּי הֲווֹ פָּרְשִׁי מֵהֲדָדֵי, שַׁמְעִינְהוּ דְּקָא אָמְרִי: אוֹרְחִין רַחִיקָא, וְצַוְותִּין בְּסִימָא.
It is like this incident, as Abaye once heard a certain man say to a certain woman: Let us rise early and go on the road. Upon hearing this, Abaye said to himself: I will go and accompany them and prevent them from violating the prohibition that they certainly intend to violate. He went after them for a distance of three parasangs in a marsh among the reeds, while they walked on the road, and they did not engage in any wrongful activity. When they were taking leave of each other, he heard that they were saying: We traveled a long distance together, and the company was pleasant company.
אֲמַר אַבָּיֵי: אִי מַאן דְּסָנֵי לִי הֲוָה, לָא הֲוָה מָצֵי לְאוֹקוֹמֵי נַפְשֵׁיהּ. אֲזַל תְּלָא נַפְשֵׁיהּ בְּעִיבּוּרָא דְּדָשָׁא וּמִצְטַעֵר. אֲתָא הָהוּא סָבָא, תְּנָא לֵיהּ: כׇּל הַגָּדוֹל מֵחֲבֵירוֹ — יִצְרוֹ גָּדוֹל הֵימֶנּוּ.
Abaye said: In that situation, if instead of that man it had been one whom I hate, a euphemism for himself, he would not have been able to restrain himself from sinning. After becoming aware of so great a shortcoming he went and leaned against the doorpost, thinking and feeling regret. A certain Elder came and taught him: Anyone who is greater than another, his evil inclination is greater than his. Therefore, Abaye should not feel regret, as his realization is a consequence of his greatness.
Even the great Amora Abaye didn't trust himself. Can we trust teenagers in our day and age to spend significant amounts of time having fun and traveling around with the opposite gender and expect nothing to happen???
To do so would require a level of naivete wrought with dangerous consequences.
